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John Ayers on March 21, 2019. (Peter Morenus/UConn Photo)

 

John E. Ayers
Associate Professor
Office: ITE 461
Phone: (860) 486-2207
Email: jayers@engr.uconn.edu

Personal Page: http://www.engr.uconn.edu/~jayers

Semiconductor Materials Research Group                                                  

Education:

  • Ph.D., Rensselaer Polytechnic Institute, 1990.
  • M.S., Rensselaer Polytechnic Institute, 1987.
  • B.S., University of Maine, 1984.

Experience:

  • 2015 – present: Chief Scientist, Epitax Engineering
  • 1996-present: Associate Professor, University of Connecticut
  • 1999-2006:  Associate Department Head, ECE,  University of Connecticut
  • 1990-1996: Assistant Professor, University of Connecticut
  • 1987-1988: Research Associate, Philips Laboratories, Briarcliff Manor, NY
  • 1984: Test Engineer, National Semiconductor, South Portland, ME
  • 1982-1983: Technician, Fairchild Semiconductor, South Portland, ME

Professional Activities:

  • Associate Editor, Journal of Electronic Materials, 2015 – present
  • Editor, Cogent Engineering, 2016 – present
  • Lead Organizer, Symposium on Semiconductor Heterostructures, Materials Science and Technology Conference, 2011 – present
  • Nanotechnology Consultant, Applied Materials Inc., 2015 – present
  • Lead Organizer, Symposium on Semiconductor Heterostructures, American Vacuum Society Meeting, 2012-2013
  • Guest Editor, Special Issue on Semiconductor Heterostructures, Journal of Electronic Materials, 2012.

Research Interests:
Heteroepitaxial growth of mismatched semiconductors; characterization of epitaxial structures, and defect engineering in heteroepitaxial materials.

Peer Reviewing – Funding Agencies

  • National Science Foundation MIP Review Panel, June 2015
  • NASA Postdoctoral Program Review, July 2014
  • NASA Postdoctoral Program Review, March 2014
  • National Science Foundation SBIR Phase I Review Panel, January 2011
  • National Science Foundation SBIR Phase I Review Panel, August 2010
  • National Science Foundation SBIR Phase I Review Panel, March 2010

Peer Reviewing – Journals:

  • ACS Applied Materials & Interfaces
  • Applied Physics A
  • Applied Physics Letters
  • Applied Physics Letters Materials
  • Applied Surface Science
  • IEEE Transactions on Electron Devices
  • International Journal of High-Speed Electronics and Systems
  • Journal of Applied Physics
  • Journal of Computational Chemistry
  • Journal of Crystal Growth
  • Journal of Crystal Growth and Design
  • Journal of Electronic Materials
  • Journal of Low-Power Electronics and Applications
  • Journal of Materials Science
  • Journal of Physics: Condensed Matter
  • Journal of Physics D
  • Journal of Vacuum Science and Technology B
  • Nanotechnology
  • Scripta Materialia
  • Semiconductor Science and Technology
  • Surface Science

Honors:

  • University of Connecticut Chapter of the American Association of University Professors Teaching Excellence: Career Award (2019).
  • University of Connecticut Provost’s Commendation for Excellence in Teaching: Fall 2017; Spring 2017; Fall 2016; Spring 2016; Fall 2015; Spring 2015; Fall 2014; Spring 2014.
  • Electrical and Computer Engineering Outstanding Teaching Award, 2016-2017.
  • Electrical and Computer Engineering Outstanding Teaching Award, 2010-2011.
  • Electrical and Computer Engineering IEEE/HKN Best Teacher Award, 2006.
  • University of Connecticut Student Organization Advisor Award, for serving as the faculty advisor to the student branch of the Institute of Electrical and Electronics Engineers (2004).
  • Electrical and Computer Engineering Excellence in Teaching Award, 2003.
  • University of Connecticut Teaching Fellow, 1999-2000.
  • School of Engineering Outstanding Teaching Award, University of Connecticut, 1999.
  • IBM Fellow, 1988-1990.
  • American Electronics Association / Analog Devices Fellow, 1984-1988.

Books:

[8] John Ayers, Runner (Kindle Direct Publishing, Middletown, DE, Dec. 2018). ISBN-13: 978-1717724335.

[7] John E. Ayers, Tedi Kujofsa, Paul Rago, and Johanna Raphael, Heteroepitaxy of Semiconductors: Theory, Growth, and Characterization, Second Edition, CRC Press, Boca Raton, FL, 2016. ISBN-13: 978-1482254358.

[6] John E. Ayers, Solution Manual for Digital Integrated Circuits: Analysis and Design, Second Edition, CRC Press, Boca Raton, FL, 2009.

[5] John E. Ayers, Digital Integrated Circuits: Analysis and Design, Second Edition, CRC Press, Boca Raton, FL, 2009. ISBN-13: 978-1420069877.

[4] John E. Ayers, Heteroepitaxy of Semiconductors: Theory, Growth, and Characterization, CRC Press, Boca Raton, FL, 2007.

[3]  John E. Ayers, Instructor’s Supplement for Digital Integrated Circuits: Analysis and Design, CRC Press, Boca Raton, FL, 2003.

[2]  John E. Ayers, Solution Manual for Digital Integrated Circuits: Analysis and Design, CRC Press, Boca Raton, FL, 2003.

[1]  John E. Ayers, Digital Integrated Circuits: Analysis and Design, CRC Press, Boca Raton, FL, 2003.

Book Chapters:

[2] J. E. Ayers, “Low Temperature and Metamorphic Buffer Layers,” in The Handbook of Crystal Growth, second edition, edited by Tatau Nishinaga, Peter Rudolph, and Thomas Kuech, Elsevier, 2014.

[1] J. E. Ayers, J. W. Steadman,and B. M. Wilamowski, “Active Filters,” in The Electrical Engineering Handbook: Electronics, Power Electronics, Optoelectronics, Microwaves, Electromagnetics, and Radar, 3rd Edition, edited by Richard C. Dorf, CRC Press, Boca Raton, FL, 2005.

Journal Papers:

[89] Md T. Islam, X. Chen, T. Kujofsa, and J. E. Ayers, “Threading dislocations in metamorphic semiconductor buffer layers containing chirped superlattices,” Intl. J. High Speed Electron. Syst., in press (2019).

[88] M. Cai, T. Kujofsa, X. Chen, Md T. Islam, and J. E. Ayers, “Optimization of graded buffer layers for metamorphic semiconductor devices,” Intl. J. High Speed Electron. Syst., in press (2019).

[87] M. Cai, T. Kujofsa, X. Chen, Md T. Islam, and J. E. Ayers, “Interaction length for dislocations in compositionally-graded heterostructures,” Intl. J. High Speed Electron. Syst., in press (2019).

[86] Md T. Islam, X. Chen, T. Kujofsa, and J. E. Ayers, “Chirped superlattices as adjustable strain platforms for metamorphic semiconductor devices,” Intl. J. High Speed Electron. Syst., 27, 1840009 (2018). doi: 10.1142/S0129156418400098

[85] F. A. Althowibi and J. E. Ayers, “Dynamical x-ray diffraction analysis of a GaAs/In0.3Ga0.7As single quantum well grown on a GaAs (001) substrate,” Intl. J. High Speed Electron. Syst., 27, 1840010 (2018). doi: 10.1142/S0129156418400104

[84] T. Kujofsa, Y. Song, and J. E. Ayers, “Model for threading dislocations in metamorphic tandem solar cells on GaAs (001) substrates,” Mater. Research Express, 5, 025909 (2018). doi: 10.1088/2053-1591/aaac41

[83] Y. Song, T. Kujofsa, and J. E. Ayers, “Threading Dislocations in InGaAs/GaAs (001) Buffer Layers for Metamorphic High Electron Mobility Transistors,” J. Electron. Mater., 47, 3474-3482 (2018). doi: 10.1007/s11664-018-6187-8

[82] X. Chen, Md T. Islam, T. Kujofsa, and J. E. Ayers, “Chirped Superlattices as Adjustable Strain Platforms for Metamorphic Semiconductor Devices,” ECS Trans., 80, 981 (2017). doi: 10.1149/08010.0981ecst

[81] F. A. Althowibi and J. E. Ayers, “Characterization of Dislocations in Semiconductor Heterostructures Using X-Ray Rocking Curve Pendellösung,” J. Electron. Mater., 47, 1158-1166 (2017). doi: 10.1007/s11664-017-5895-9

[80] T. Kujofsa and J. E. Ayers, “Electric circuit model analogy for equilibrium lattice relaxation in semiconductor heterostructructures,” J. Electron. Mater., 47, 173-187 (2017). doi: 10.1007/s11664-017-5750-z

[79] F. A. Althowibi and J. E. Ayers, “Simulated x-ray diffraction from pseudomorphic GaAs/In0.3Ga0.7As superlattice high electron mobility transistor heterostructures on GaAs (001) substrates,” J. Vac. Sci. Technol. B, 35, 03D108 (2017). doi: 10.1116/1.4981015

[78] F. A. Althowibi and J. E. Ayers, “Dynamical x-ray diffraction analysis of triple-junction solar cells on germanium (001) substrates,” Intl. J. High Speed Electron. Syst., 26, 1740011 (2017).  doi: 10.1142/S0129156417400110

[77] T. Kujofsa and J. E. Ayers, “Critical layer thickness: Theory and experiment in the ZnSe / GaAs (001) material system,” Intl. J. High Speed Electron. Syst., 26, 1740020 (2017). doi: 10.1142/S0129156417400201

[76] F. A. Althowibi and J. E. Ayers, “X-ray analysis of metamorphic InxGa1-xAs/InyGa1-yAs superlattices on GaAs (001) Substrates,” J. Vac. Sci. Technol. B, 35, 03D105 (2017). doi: 10.1116/1.4979323

[75] T. Kujofsa and J. E. Ayers, “Progression of strain relaxation in linearly-graded GaAs1-yPy/GaAs (001) epitaxial layers approximated by a finite number of sublayers,” Intl. J. High Speed Electron. Syst., 26, 1740007 (2017). doi: 10.1142/S0129156417400079

[74] P. B. Rago and J. E. Ayers, “Mosaic Crystal Model for Dynamical X-ray Diffraction from Step-Graded InxGa1-x/As and InxAl1-xAs / GaAs (001) Metamorphic Buffers and Device Structures,” Intl. J. High Speed Electron. Syst., 26, 1740019 (2017). doi: 10.1142/S0129156417400195

[73] T. Kujofsa and J. E. Ayers, “Strain compensation in a semiconducting device structure using an intentionally mismatched uniform buffer layer,” Semicond. Sci. Technol., 31, 125005 (2016). doi:10.1088/0268-1242/31/12/125005

[72] T. Kujofsa and J. E. Ayers, “Electric circuit model for strained-layer epitaxy,” Semicond. Sci. Technol., 31, 115014 (2016).

[71] T. Kujofsa, S. Cheruku, D. Sidoti, S. Xhurxhi, F. Obst, J. P. Correa, B. Bertoli, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Apparent critical layer thickness in ZnSe/GaAs (001) heterostructures and the role of experimental resolution,” J. Vac. Sci. Technol. B, 34, 051201 (2016).

[70] T. Kujofsa and J. E. Ayers, “Dynamics of kinetically limited strain and threading dislocations in temperature- and compositionally graded ZnSSe/GaAs (001) metamorphic heterostructures,” J. Electron. Mater., 45, 4580 (2016).

[69] F. Althowibi, P. B. Rago, and J. E. Ayers, “X-ray diffraction analysis for step- and linearly-graded InxGa1-x/GaAs (001) heterostructures using various hkl reflections,” J. Vac. Sci. Technol. B, 34, 041209 (2016). doi: 10.1116/1.4949517

[68] T. Kujofsa and J. E. Ayers, “Equilibrium lattice relaxation and misfit dislocations in step-graded InxGa1-xAs/GaAs (001) and InxAl1-xAs/GaAs (001) metamorphic buffer layers,” J. Electron. Mater., 45, 2831 (2016). doi: 10.1007/s11664-016-4377-9

[67] T. Kujofsa and J. E. Ayers, “Resolution of x-ray rocking curve measurements made with finite counting statistics,” Int. J. Hi. Spe. Ele. Syst., 24, 1550007 (2015). doi: 10.1142/S012915641550007X

[66] T. Kujofsa and J. E. Ayers, “Equilibrium lattice relaxation and misfit dislocations in continuously- and step-graded InxGa1-xAs/GaAs (001) and GaAs1-yPy/GaAs (001) metamorphic buffer layers,” Intl. J. High Speed Electron. Syst., 24, 1520009 (2015). doi 10.1142/S0129156415200098

[65] E. Suarez, P.-Y. Chan, M. Gogna, J. E. Ayers, and F. C. Jain, “Fabrication and simulation of InGaAs field-effect transistors with II-VI tunneling insulators,” J. Electron. Mater., 44, 3064 (2015). doi 10.1007/s11664-015-3769-6

[64] T. Kujofsa and J. E. Ayers, “Evolution of Kinetically-Limited Lattice Relaxation and  Threading Dislocations in Temperature-Graded  ZnSe/GaAs (001) Metamorphic Heterostructures,” J. Electron. Mater., 44, 3030 (2015).

[63] P. B. Rago and J. E. Ayers, “Comparison of the phase-invariant and mosaic crystal models for dynamical x-ray diffraction from metamorphic InxGa1-xAs / GaAs (001) structures,” J. Vac. Sci. Technol. B, 33, 021204 (2015).

[62] T. Kujofsa and J. E. Ayers, “Comparison of continuously- and step-graded ZnSySe1-y/GaAs (001) metamorphic buffer layers,” J. Electron. Mater., 43, 3047 (2014).  doi: 10.1007/s11664-014-3205-3

[61] T. Kujofsa and J. E. Ayers, “Threading dislocations in S-graded ZnSxSe1-x/GaAs (001) metamorphic buffer layers,” Int. J. High Speed Electron. Sys., 23, 1420005 (2014). doi: 10.1142/S0129156414200055

[60] E. Suarez, P.-Y. Chan, M. Gogna, J. E. Ayers, E. Heller, and F. C. Jain, “ZnS/ZnMgSeTe/ZnS II-VI energy barrier for InGaAs substrates,” Intl. J. High Speed Electron. Sys., 23, 1450013 (2014).  doi: 10.1142/S012915641450013X.

[59] J. Raphael, B. Bertoli, and J. E. Ayers, “Equilibrium strain and dislocation density in nitride based heterostructures,” Intl. J. High Speed Electron. Sys., 23, 1450009 (2014). doi: 10.1142/S0129156414500098

[58] T. Kujofsa and J. E. Ayers, “Lattice relaxation and misfit dislocations in nonlinearly graded InxGa1-xAs/GaAs (001) and GaAs1-yPy/GaAs (001) Metamorphic Buffer Layers,” J. Vac. Sci. Technol. B, 32, 031205 (2014).

[57] T. Kujofsa, S. Cheruku, W. Yu, B. Outlaw, S. Xhurxhi, F. Obst, D. Sidoti, B. Bertoli, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Relaxation dynamics and threading dislocations in ZnSe and ZnSySe1-y/GaAs (001) heterostructures,” J. Electron. Mater., 42, 2764 (2013).

[56] T. Kujofsa and J. E. Ayers, “Design of dislocation-compensated ZnSySe1-y/GaAs (001) heterostructures,” J. Electron. Mater., 42, 3034 (2013).

[55] T. Kujofsa, A. Antony, S. Xhurxhi, F. Obst, D. Sidoti, B. Bertoli, S. Cheruku, J. P. Correa, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Design of S-graded buffer layers for metamorphic ZnSySe1-y/GaAs (001) semiconductor devices,” J. Electron. Mater., 42, 3408 (2013)

[54] E. Suarez, P.-Y. Chan, M. Lingalugari, J. E. Ayers, E. Heller, and F. C. Jain, “Quantum dot gate three-state and nonvolatile memory field-effect transistors using a ZnS/ZnMgS/ZnS heteroepitaxial stack as a tunnel insulator on silicon-on-insulator substrates,” J. Electron. Mater., 42, 3275 (2013).

[53] P. Y. Chan, M. Gogna, E. Suarez, F. Al-Amoody, S. Karmakar, B. I. Miller, E. K. Heller, J. E. Ayers, and F. C. Jain, “Fabrication and Simulation of an indium gallium arsenide quantum-dot-gate field effect transistor (QDG-FET) with ZnMgS as a tunnel gate insulator,” J. Electron. Mater., 42, 3259 (2013).

[52] P. B. Rago, F. C. Jain, and J. E. Ayers, “The Effect of Epilayer Tilt on Dynamical X-Ray Diffraction from Uniform Heterostructures with Asymmetric Dislocation Densities,” J. Electron. Mater., 42, 3066 (2013).

[51] T. Kujofsa, W. Yu, S. Cheruku, B. Outlaw, S. Xhurxhi, F. Obst, D. Sidoti, B. Bertoli, P. B. Rago, E. N. Suarez, F. C. Jain and J. E. Ayers, “Plastic Flow and Dislocation Compensation in ZnSySe1-y/GaAs (001) Heterostructures,” J. Electron. Mater., 41, 2993 (2013).

[50] P. B. Rago and J. E. Ayers, “Dynamical x-ray diffraction from InxGa1-xAs heterostructures with dislocations,” J. Electron. Mater., 42, 2450 (2013).

[49] P.-Y. Chan, E. Suarez, M. Gogna, B. I. Miller, E. K. Heller, J. E. Ayers, and F. C. Jain, “Indium Gallium Arsenide Quantum Dot Gate Field-Effect Transistor Using II-VI Tunnel Insulators Showing Three-State Behavior,” J. Electron. Mater., (2012). doi: 10.1007/s1164-012-2176-5

[48] P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Dynamical X-Ray Diffraction from ZnSySe1-y/GaAs (001) Multilayers and Superlattices with Dislocations,” J. Electron. Mater., 41, 2846 (2012). doi: 10.1007/s11664-012-2012-y

[47] S. Xhurxhi, F. Obst, D. Sidoti, B. Bertoli, T. Kujofsa, S. Cheruku, J. P. Correa, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “S-Graded Buffer Layers for Lattice-Mismatched Heteroepitaxial Devices,” J. Electron. Mater., 40, 2348 (2011).

[46] D. Sidoti, S. Xhurxhi, T. Kujofsa, S. Cheruku, J. P. Correa, B. Bertoli, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Initial Misfit Dislocations in a Graded Heteroepitaxial Layer,” J. Appl. Phys., 109, 1 (2011).

[45] P. Shimpi, Y. Ding, E. Suarez, J. E. Ayers, and P.-X. Gao, “Annealing induced nanostructure and photoluminescence property evolution in solution-processed Mg-alloyed ZnO nanowires,” Appl. Phys. Lett., 97, 103104 (2010).

[44] E. Suarez, M. Gogna, F. Al-Amoody, S. Karmakar, J. E. Ayers, E. Heller, and F. C. Jain, “Nonvolatile Memories using Quantum Dot (QD) Floating Gate Assembled on II-VI Tunnel Insulator,” J. Electron. Mat., 39, 903 (2010).

[43] B. Bertoli, D. Sidoti, S. Xhurxhi, T. Kujofsa, S. Cheruku, J. Reed, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Equilibrium strain and dislocation density in exponentially graded Si(1-x)Ge(x)/Si (001),” J. Appl. Phys., 108, 113525 (2010).

[42] D. Sidoti, S. Xhurxhi, T. Kujofsa, S. Cheruku, J. Reed, B. Bertoli, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Critical layer thickness in exponentially-graded heteroepitaxial layers,” J. Electron. Mat., 39, 1140 (2010).

[41] J. F. Ocampo, B. Bertoli, P. B. Rago, E. N. Suarez, D. Shah, F. C. Jain, and J. E. Ayers, “Asymmetric Dislocation Densities in Forward-Graded ZnSySe1-y / GaAs (001) Heterostructures,” J. Electron. Mat., 39, 391 (2010).

[40] B. Yarlagadda, A. Rodriguez, P. Li, R. Velampati, J. E. Ayers, and F. C. Jain, “A quantitative model for the interpretation of RAV (Rocking Curve Azimuthal Variation) results from heteroepitaxial semiconductor layers,” J. Cryst. Growth, 312, 886 (2010).

[39] B. Bertoli, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Dislocations and Strain Relief in Reverse-Graded Semiconductor Layers,” Semicond. Sci. Technol., 24,125006 (2009).

[38] B. Bertoli, E. N. Suarez, J. E. Ayers, and F. C. Jain, “Misfit dislocation density and strain relaxation in graded semiconductor heterostructures with arbitrary composition profiles,” J. Appl. Phys., 106, 073519 (2009).

[37] J. F. Ocampo, E. Suarez, D. Shah, P. B. Rago, F. C. Jain, and J. E. Ayers, “Overshoot graded layers for defect engineering in heteroepitaxial semiconductor structures,” J. Electron. Mat., 37, 1035 (2008).

[36] J. E. Ayers, “Compliant Substrates for Heteroepitaxial Semiconductor Devices: Theory, Experiment, and Current Directions,” J. Electron. Mat., 37, 1511 (2008).

[35] B. Yarlagadda, A. Rodriguez, P. Li, R. Velampati, J. F. Ocampo, E. N. Suarez, P. B. Rago, D. Shah, J. E. Ayers, and F. C. Jain, “X-ray characterization of dislocation density asymmetries in heteroepitaxial semiconductors,” Appl. Phys. Lett., 92, 202103 (2008).

[34] J. E. Ayers, “Critical layer thickness in compositionally-graded semiconductor layers with non-zero interfacial mismatch,” Semicond. Sci. Technol., 23, 045018 (2008).

[33] J. E. Ayers, “Multiple Critical Layer Thicknesses in Retro-Graded Heterostructures,” Appl. Phys. Lett., 92, 102104 (2008).

[32] B. Yarlagadda, A. Rodriguez, P. Li, B. I. Miller, F. C. Jain, and J. E. Ayers, “Elastic Strains in Heteroepitaxial ZnSe1-xTex on InGaAs/InP (001),” J. Electron. Mat., 35, 1327-1332 (2006).

[31] P. Li, A. Rodriguez, B. Yarlagadda, R. Velampati, J. E. Ayers, and F. C. Jain, “Electrical properties of oxidized polycrystalline silicon as a gate insulator for n-type 4H-SiC MOS devices,” Solid State Electron., 49, 2002-2005 (2005).

[30] D. W. Parent, A. Rodriguez, J. E. Ayers, and F. C. Jain, “Photoassisted MOVPE grown (n)ZnSe/(p+)GaAs heterojunction solar cells,” Solid-State Electron., 47, 595 (2003).

[29] X. G. Zhang, A. Rodriguez, P. Li, F. C. Jain, and J. E. Ayers, “Patterned heteroepitaxial processing applied to ZnSe and ZnS0.02Se0.98 on GaAs (001),” J. Appl. Phys., 91, 3912 (2002).

[28] X. G. Zhang, A. Rodriguez, P. Li, F. C. Jain, and J. E. Ayers, “A Novel Approach for the Complete Removal of Threading Dislocations from ZnSe on GaAs (001),” J. Electronic Materials, 30, 667 (2001).

[27] D. W. Parent, A. Rodriguez, and F. C. Jain, “The Photoassisted MOVPE Growth of ZnMgSSe,” J. Cryst. Growth, 224, 212 (2001).

[26] D. W. Parent, A. Rodriguez, P. Li, X. G. Zhang, G. Zhao, J. E. Ayers, and F. C. Jain, “The photoassisted MOVPE growth of ZnSSe using tertiary-butylmercaptan,” J. Electron. Mat., 29, 713 (2000).

[25] X. G. Zhang, A. Rodriguez, X. Wang, P. Li, F. C. Jain, and J. E. Ayers, “Complete Removal of Threading Dislocations from Mismatched Layers by Patterned Heteroepitaxial Processing,” Appl. Phys. Lett., 77, 2524 (2000).

[24] X. G. Zhang, D. W. Parent, P. Li, A. Rodriguez, G. Zhao, J. E. Ayers, and F. C. Jain, “X-Ray Rocking Curve Analysis of Tetragonally Distorted Ternary Semiconductors on Mismatched (001) Substrates,” J. Vac. Sci. Technol. B, 18, 1375 (2000).

[23] X. G. Zhang, P. Li, D. W. Parent, G. Zhao, J. E. Ayers, and F. C. Jain, “Comparison of x-ray diffraction methods for determination of the critical layer thickness for dislocation multiplication,” J. Electron. Mat., 28, 553 (1999).

[22] X. G. Zhang, P. Li, G. Zhao, D. W. Parent, F. C. Jain, and J. E. Ayers, “Removal of threading dislocations from patterned heteroepitaxial semiconductors by glide,” J. Electron. Mat., 27, 1248 (1998).

[21] K. X. Bao, R. Mo, X. G. Zhang, S. Kalisetty, M. Gokhale, J. Robinson, G. Zhao, J. E. Ayers, and F. C. Jain, “Compositional control of CdZnSe grown by photoassisted organometallic vapor phase epitaxy,” J. Cryst. Growth, 170, 497 (1997).

[20] X. G. Zhang, S. Kalisetty, J. Robinson, G. Zhao, D. W. Parent, J. E. Ayers, and F. C. Jain, “Structural properties of ZnSSe/ZnSe/GaAs (001) heterostructures grown by photoassisted metalorganic vapor phase epitaxy,” J. Cryst. Growth, 174, 726 (1997).

[19] D. W. Parent, S. Kalisetty, X. G. Zhang, G. Zhao, W. Zappone, J. Robinson, E. Heller, J. E. Ayers, and F. C. Jain, “A comparison of ethyl iodide and hydrogen chloride for doping ZnSe grown by photoassisted MOVPE,” J. Electron. Mat., 26, 710 (1997).

[18] X. G. Zhang, S. Kalisetty, J. Robinson, G. Zhao, D. W. Parent, J. E. Ayers, and F. C. Jain, “Structural properties of ZnSSe/ZnSe/GaAs (001) heterostructures grown by photoassisted metalorganic vapor phase epitaxy,” J. Electron. Mat., 26, 697 (1997).

[17] M. R. Gokhale, K. X. Bao, P. D. Healey, F. C. Jain, and J. E. Ayers, “Role of cadmium in enhancing optical properties and chlorine doping of photo-assisted OMVPE-grown ZnSe,” J. Electron. Mat., 25, 207 (1996).

[16] S. Kalisetty, M. Gokhale, K. Bao, J. E. Ayers, and F. C. Jain, “The influence of impurities on the dislocation behavior in heteroepitaxial ZnSe on GaAs,” Appl. Phys. Lett., 68, 1693 (1996).

[15] P. D. Healey and J. E. Ayers, “The instrumental broadening function of the Bartels five-crystal x-ray diffractometer,” Acta Cryst., A52, 245 (1996).

[14] M. R. Gokhale, K. X. Bao, P. D. Healey, F. C. Jain, and J. E. Ayers, “Factors influencing low-temperature photo-assisted OMVPE growth of ZnSe,” J. Cryst. Growth, 165, 25 (1996).

[13] P. D. Healey, K. Bao, M. Gokhale, J. E. Ayers, and F. C. Jain, “X-ray determination of the dislocation densities in semiconductor crystals using a Bartels five-crystal diffractometer,” Acta. Cryst. Sec. A, A51, 498 (1995).

[12] K. Bao, P. D. Healey, M. Gokhale, J. E. Ayers, and F. C. Jain, “Properties of vapor phase epitaxial zinc selenide codoped with cadmium and chlorine,” Appl. Phys. Lett., 67, 1098 (1995).

[11] J. E. Ayers, “New model for the thickness and mismatch dependencies of threading dislocation densities in mismatched heteroepitaxy,” J. Appl. Phys., 78, 3724 (1995).

[10] J. E. Ayers, “The measurement of threading dislocation densities in semiconductor crystals by x-ray diffraction,” J. Cryst. Growth, 135, 71 (1994).

[9] J. E. Ayers and L. J. Schowalter, “Comment on ‘Measurement of the activation barrier to nucleation of dislocations in thin films,’ “ Phys. Rev. Lett., 72, 4055 (1994).

[8] J. E. Ayers, L. J. Schowalter, and S. K. Ghandhi, “Post-growth thermal annealing of GaAs on Si (001) grown by organometallic vapor phase epitaxy,” J. Cryst. Growth, 125, 329 (1992).

[7] J. E. Ayers, L. J. Schowalter, and S. K. Ghandhi, “Crystallographic tilting of heteroepitaxial layers,” J. Cryst. Growth, 113, 430 (1991).

[6] L. J. Schowalter, J. E. Ayers, S. K. Ghandhi, S. Hashimoto, W. M. Gibson, F. K. LeGoues, and P. A. Claxton, “Strain in Epitaxial GaAs on CaF2/Si (111),” J. Vac. Sci Technol. B, 8, 246 (1990).

[5] J. Ayers and S. K. Ghandhi, “The epitaxy of germanium on gallium arsenide,” J. Cryst. Growth, 89, 371 (1988).

[4] J. Ayers and J. Ladell, “The spectral widths of the Cu k alpha lines,” Phys. Rev. A, 37, 2404 (1988).

[3] I. B. Bhat, K. Patel, N. R. Taskar, J. E. Ayers, and S. K. Ghandhi, “X-ray diffraction studies of CdTe grown on InSb,” J. Cryst. Growth, 88, 23 (1988).

[2] S. K. Ghandhi and J. E. Ayers, “Strain and misorientation in GaAs grown on Si (001) by organometallic epitaxy,” Appl. Phys. Lett., 53, 1204 (1988).

[1] S. K. Ghandhi and J. E. Ayers, “The chemical etching of germanium, J. Electrochem. Soc., 135, 2053 (1988).

 

Google Scholar Citations: http://scholar.google.com/citations?user=BaGZ8s4AAAAJ

 

Conference Presentations and Proceedings:

[110] T. Kujofsa, M. Cai, Md T. Islam, and J. E. Ayers, “Theoretical optimization of graded semiconductor buffer layers,” Materials Science and Technology Conference, Columbus, OH (Oct. 14-18, 2018).

[109] Md T. Islam, X. Chen, T. Kujofsa, and J. E. Ayers, “Comparison of chirped and unchirped superlattices as dislocation filters for metamorphic InGaAs/GaAs (001) devices,” Materials Science and Technology Conference, Columbus, OH (Oct. 14-18, 2018).

[108] T. Kujofsa and J. E. Ayers, “Plastic flow in lattice-mismatched III-V heterostructures,” Materials Science and Technology Conference, Columbus, OH (Oct. 14-18, 2018).

[107] M. Cai, T. Kujofsa, X. Chen, Md T. Islam, and J. E. Ayers, “Interaction length for dislocations in compositionally-graded and multilayered semiconductor heterostructures,” Connecticut Symposium on Microelectronics and Optoelectronics, Orange, CT (April 4, 2018).

[106] Md T. Islam, X. Chen, T. Kujofsa, and J. E. Ayers, “Threading dislocations in metamorphic semiconductor buffer layers containing chirped superlattices,” Connecticut Symposium on Microelectronics and Optoelectronics, Orange, CT (April 4, 2018).

[105] T. Kujofsa, M. Cai, X. Chen, Md T. Islam, and J. E. Ayers, “Optimization of graded buffer layers for metamorphic semiconductor devices,” Connecticut Symposium on Microelectronics and Optoelectronics, Orange, CT (April 4, 2018).

[104] X. Chen, Md T. Islam, T. Kujofsa, and J. E. Ayers, “Comparison of chirped and unchirped superlattices as buffers for metamorphic InGaAs/GaAs (001) devices,” IEEE MIT Undergraduate Research Technology Conference, Cambridge, MA (Nov. 3-5, 2017).

[103] T. Kujofsa and J. E. Ayers, “Thermal cycle annealing and its effect on the threading dislocation density in GaAs/Si (001),” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 8-12, 2017).

[102] T. Kujofsa and J. E. Ayers, “Application of a circuit model for strained epitaxy to continuously-graded layers with exponential profiles,” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 8-12, 2017).

[101] F. A. Althowibi and J. E. Ayers, “X-ray dynamical diffraction analysis of Al0.4Ga0.6As/GaAs/In0.15Ga0.85As separate confinement heterostructure (SCH) laser grown on a GaAs (001) substrate,” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 8-12, 2017).

[100] Y. Song, T. Kujofsa, and J. E. Ayers, “Bi-parabolic graded buffer layers for metamorphic devices,” 232nd Meeting of the Electrochemical Society, National Harbor, MD (Oct. 1-5, 2017).

[99] X. Chen, Md T. Islam, T. Kujofsa, and J. E. Ayers, “Comparison of chirped superlattices and linearly-graded buffer layers as adjustable-strain platforms for metamorphic InGaAs/GaAs (001) devices,” 232nd Meeting of the Electrochemical Society, National Harbor, MD (Oct. 1-5, 2017).

[98] Md T. Islam, X. Chen, T. Kujofsa, and J. E. Ayers, “Chirped superlattices as adjustable strain platforms for metamorphic semiconductor devices,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 5, 2017).

[97] T. Kujofsa and J. E. Ayers, “”Metamorphic buffer layers with bi-parabolic compositional profiles,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 5, 2017).

[96] F. Althowibi and J. E. Ayers, “Dynamical x-ray diffraction analysis of a GaAs/In0.3Ga0.7As/GaAs single quantum well grown on a GaAs (001) substrate,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 5, 2017).

[95] T. Kujofsa and J. E. Ayers, “Novel electrical circuit model for the design of InGaAs/GaAs (001) strained-layer superlattices,” American Vacuum Society 63rd International Symposium and Exhibition, Nashville, TN (November 7-11, 2016).

[94] F. Althowibi and J. E. Ayers, “X-ray diffraction from pseudomorphic GaAs/In0.3Ga0.7As superlattice high electron mobility transistor heterostructures on GaAs (001) substrates,” American Vacuum Society 63rd International Symposium and Exhibition, Nashville, TN (November 7-11, 2016).

[93] F. Althowibi and J. E. Ayers, “X-ray analysis of metamorphic InxGa1-xAs/InyGa1-yAs superlattices on GaAs (001) substrates,” American Vacuum Society 63rd International Symposium and Exhibition, Nashville, TN (November 7-11, 2016).

[92] F. Althowibi and J. E. Ayers, “X-ray rocking curve Pendellosung: a sensitive tool for the characterization of dislocations in pseudomorphic high electron mobility transistors,” Materials Science and Technology Conference, Salt Lake City, UT (October 23-27, 2016).

[91] T. Kujofsa and J. E. Ayers, “Electrical circuit model for InGaAs/GaAs (001) strained-layer heterostructures,” Materials Science and Technology Conference, Salt Lake City, UT (October 23-27, 2016).

[90] Y. Song, T. Kujofsa, and J. E. Ayers, “Threading dislocations in InGaAs/GaAs (001) buffer layers for metamorphic high electron mobility transistors,” Materials Science and Technology Conference, Salt Lake City, UT (October 23-27, 2016).

[89] Y. Song, T. Kujofsa, and J. E. Ayers, “Design of graded buffer layers for tandem solar cells on GaAs (001) substrates,” Materials Science and Technology Conference, Salt Lake City, UT (October 23-27, 2016).

[88] T. Kujofsa and J. E. Ayers, “Application of an electrical circuit model to study strain compensation in ZnSSe/GaAs (001) heterostructures,” U. S. Workshop on the Physics and Chemistry of II-VI Compounds, Baltimore, MD (October 17-19, 2016).

[87] T. Kujofsa and J. E. Ayers, “New electrical circuit model for relaxation in strained-layer heteroepitaxy,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 6, 2016).

[86] F. Althowibi and J. E. Ayers, “Dynamical x-ray diffraction analysis of triple-junction solar cells on Ge (001) substrates,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 6, 2016).

[85] T. Kujofsa and J. E. Ayers, “Apparent critical layer thickness in ZnSe/GaAs (001) heterostructures and the role of experimental resolution,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 6, 2016).

[84] T. Kujofsa and J. E. Ayers, “Lattice Relaxation in Multilayered Si1-xGex/Si (001) Metamorphic Heterostructures,” American Vacuum Society 62th International Symposium and Exhibition, San Jose, CA (October 19-23, 2015).

[83] T. Kujofsa and J. E. Ayers, “The Dynamics of Kinetically-Limited Strain and Threading Dislocation in Temperature- and Compositionally-Graded ZnSSe/GaAs (001) Metamorphic Heterostructures,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, Chicago, IL (October 7-9, 2015).

[82] G. G.Gutierrez, N. Kulla, P. R. S. Vicente, T. Kujofsa, and J. E. Ayers, “Misfit Dislocations and Strain in Inverted Metamorphic Triple-Junction Solar Cells on GaAs (001) Substrates,” Materials Science and Technology Conference, Columbus, OH, Oct. 4-8, 2015.

[81] T. Kujofsa and J. E. Ayers, “Strain Relaxation and Threading Dislocations of ZnSySe1-y/GaAs (001) Heterostructures Involving Super-Lattice Metamorphic Buffer Layers,” Materials Science and Technology Conference, Columbus, OH, Oct. 4-8, 2015.

[80]  F. A. Althowibi, P. B. Rago, and J. E. Ayers, “Dynamical x-ray diffraction from inverted metamorphic triple-junction solar cells on GaAs substrates,” Materials Science and Technology Conference, Columbus, OH, Oct. 4-8, 2015.

[79] T. Kujofsa and J. E. Ayers, “Equilibrium modeling of strain compensation in multilayered and ungraded InxGa1-xAs/GaAs (001) heterostructures,” Materials Science and Technology Conference, Columbus, OH, Oct. 4-8, 2015.

[78] F. A. Althowibi, P. B. Rago, and J. E. Ayers, “Determination of dislocation densities in metamorphic multijunction solar cells by high-resolution x-ray diffraction,” Materials Science and Technology Conference, Columbus, OH, Oct. 4-8, 2015.

[77] J. Raphael and J. E. Ayers, Dislocation dynamics and lattice relaxation in InGaN/GaN (0001) heterostructures,” Materials Science and Technology Conference, Columbus, OH, Oct. 4-8, 2015.

[76] T. Kujofsa and J. E. Ayers, “Design of super lattice metamorphic buffer layers for high built-in residual strain,” Connecticut Symposium on Microelectronics and Optoelectronics, Bridgeport, CT (April 1, 2015).

[75] T. Kujofsa and J. E. Ayers, “Kinetically-limited lattice relaxation in linearly- and no-linearly-compositionally-graded InxGa1-xAs/GaAs (001) metamorphic heterostructures,” American Vacuum Society 61st International Symposium and Exhibition, Baltimore, MD (Nov. 10-14, 2014).

[74] T. Kujofsa and J. E. Ayers, “Evolution of kinetically-limited lattice relaxation and threading dislocations in temperature-graded ZnSe/GaAs (001) metamorphic heterostructures,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, Baltimore, MD (October 20-23, 2014).

[73] P. Rago and J. E. Ayers, “Analysis of linearly-graded InGaAs/GaAs (001) metamorphic buffer layers using various hkl diffraction profiles,” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 12-16, 2014).

[72] T. Kujofsa and J. E. Ayers, “Equilibrium lattice relaxation and misfit dislocations in step-graded InxGa1-xAs/GaAs (001) and InxAl1-xAs/GaAs (001) metamorphic buffer layers,” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 12-16, 2014).

[71] P. Rago amd J. E. Ayers, “Mosaic crystal model for x-ray diffraction from step-graded and linearly-graded InGaAs/GaAs (001),” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 12-16, 2014).

[70] T. Kujofsa and J. E. Ayers, “Evolution of lattice relaxation and threading dislocations in ZnSySe1-y/GaAs (001) metamorphic buffer layers,” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 12-16, 2014).

[69] M. O. Jones, J. E. Raphael, and J. E. Ayers, “Strain relaxation and misfit dislocations in InxGa1-xN/GaN heterostructures with a-type dislocations,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 9, 2014).

[68] P. B. Rago and J. E. Ayers, “Mosaic crystal model for dynamical x-ray diffraction from step-graded InGaAs/GaAs (001) metamorphic buffers,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 9, 2014).

[67] T. Kujofsa and J. E. Ayers, “Equilibrium lattice relaxation and misfit dislocations in continuously- and step-graded InxGa1-xAs/GaAs (001) and GaAs1-yPy/GaAs (001) Metamorphic Buffer Layers,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 9, 2014).

[66] T. Kujofsa and J. E. Ayers, “Resolution of x-ray rocking curve measurements made with finite counting statistics,” Connecticut Symposium on Microelectronics and Optoelectronics, Storrs, CT (April 9, 2014).

[65] S. Xhurxhi, E. N. Suarez, and J. E. Ayers, “Half-loop model for equilibrium strain relaxation in zinc blende semiconductor heterostructures,” Materials Science and Technology Conference, Montreal, Quebec (Oct. 27-31, 2013).

[64] J. E. Raphael, B. Bertoli, and J. E. Ayers, “Dislocation geometry and equilibrium strain relaxation in InGaN/GaN (0001) heterostructures,” Materials Science and Technology Conference, Montreal, Quebec (Oct. 27-31, 2013).

[63] T. Kujofsa, E. N. Suarez, B. Bertoli, F. C. Jain, and J. E. Ayers, “Dislocation compensation in ungraded ZnSySe1-y/GaAs (001) multilayer heterostructures,” Materials Science and Technology Conference, Montreal, Quebec (Oct. 27-31, 2013).

[62] P. B. Rago, J. E. Raphael, and J. E. Ayers, “Mosaic crystal model for dynamical x-ray diffraction from InGaAs/GaAs (001) metamorphic heterostructures,” Materials Science and Technology Conference, Montreal, Quebec (Oct. 27-31, 2013).

[61] J. E. Raphael, B. Bertoli, and J. E. Ayers, “Equilibrium strain relaxation and dislocations in nitride device structures on semi-polar substrates,” Materials Science and Technology Conference, Montreal, Quebec (Oct. 27-31, 2013).

[60] S. Xhurxhi, E. N. Suarez, A. Antony, and J. E. Ayers, “Half-loop model for equilibrium strain in tensile and compressive layers on InP (001) substrates,” Materials Science and Technology Conference, Montreal, Quebec (Oct. 27-31, 2013).

[59] T. Kujofsa, E. N. Suarez, and J. E. Ayers, “Non-equilibrium relaxation and threading dislocations in InGaAs/GaAs metamorphic buffer layers for devices,” Materials Science and Technology Conference, Montreal, Quebec (Oct. 27-31, 2013).

[58] P. B. Rago, J. E. Raphael, and J. E. Ayers, “Mosaic crystal model for dynamical x-ray diffraction from metamorphic device heterostructures,” Materials Science and Technology Conference, Montreal, Quebec (Oct. 27-31, 2013).

[57] T. Kujofsa, P. B. Rago, and J. E. Ayers, “Lattice relaxation and misfit dislocations in nonlinearly graded InxGa1-xAs/GaAs (001) and GaAs1-yPy/GaAs (001) metamorphic buffer layers,” American Vacuum Society 60th International Symposium and Exhibition, Long Beach, CA (Oct. 27- Nov. 1, 2013).

[56] P. B. Rago and J. E. Ayers, “A comparison of phase invariant and mosaic crystal models for dynamical diffraction from InGaAs/GaAs (001) heterostructures containing dislocations,” American Vacuum Society 60th International Symposium and Exhibition, Long Beach, CA (Oct. 27- Nov. 1, 2013).

[55] P.-Y. Chan, M. Lingalugari, E. N. Suarez, J. E. Ayers, and F. C. Jain, “Indium-Gallium-Arsenide Quantum-Dot Gate Non-Volatile Memory FET Using II-VI Gate Insulators: Fabrication and Simulation,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, Chicago, IL (October 1-3, 2013).

[54] E. N. Suarez, P.-Y. Chan, M. Gogna, J. E. Ayers, and F. C. Jain, “Non-Volatile Memory FETs Using II-VI Tunneling Insulators on SOI Substrates,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, Chicago, IL (October 1-3, 2013).

[53] T. Kujofsa and J. E. Ayers, “Comparison of continuously- and step-graded ZnSySe1-y/GaAs (001) metamorphic buffer layers,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, Chicago, IL (October 1-3, 2013).

[52] E. N. Suarez, P.-Y. Chan, M. Gogna, F. Al-Amoody, S.  Karmakar, J. E. Ayers, E. Heller, and F. C. Jain, “ZnS/ZnMgSeTe/ZnS Lattice-Matched II-VI Energy Barrier for InGaAs substrates,” Connecticut Symposium on Microelectronics and Optoelectronics, New Haven, CT (March 13, 2013).

[51] T. Kujofsa and J. E. Ayers, “Threading dislocations in S-graded ZnSySe1-y/GaAs (001) heterostructures,” Connecticut Symposium on Microelectronics and Optoelectronics, New Haven, CT (March 13, 2013).

[50] J. E. Raphael, B. Bertoli, and J. E. Ayers, “Equilibrium strain and dislocation density in nitride based heterostructures,” Connecticut Symposium on Microelectronics and Optoelectronics, New Haven, CT (March 13, 2013).

[49] E. Suarez, P.-Y. Chan, M. Lingalugari, J. E. Ayers, E. Heller, and F. C. Jain, “Quantum dot gate three-state and nonvolatile memory field-effect transistors using a ZnS/ZnMgS/ZnS heteroepitaxial stack as a tunnel insulator on silicon-on-insulator substrates,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, Seattle, WA (Nov. 27-29, 2012).

[48] P. Y. Chan, M. Gogna, E. Suarez, F. Al-Amoody, S. Karmakar, B. I. Miller, E. K. Heller, J. E. Ayers, and F. C. Jain, “Fabrication and Simulation of an indium gallium arsenide quantum-dot-gate field effect transistor (QDC-FET) with ZnMgS as a unnel gate insulator,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, Seattle, WA (Nov. 27-29, 2012).

[47] P. B. Rago and J. E. Ayers, “The Effect of Epilayer Tilt on Dynamical X-ray Diffraction from a Uniform Heterostructure with Asymmetric Dislocation Densities,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, Seattle, WA (Nov. 27-29, 2012).

[46] T. Kujofsa and J. E. Ayers, “Design of Dislocation-Compensated ZnSySe1-y/GaAs (001) Heterostructures,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, Seattle, WA (Nov. 27-29, 2012).

[45] P. B. Rago and J. E. Ayers, “Dynamical X-ray Diffraction from Semiconductor Heterostructures with Asymmetric Dislocation Densities,” American Vacuum Society 59th International Symposium and Exhibition, Tampa, FL (Oct. 28 – Nov. 2, 2012).

[44] T. Kujofsa and J. E. Ayers, “Dislocation Compensation in Ungraded ZnSySe1-y/GaAs (001) Heterostructures,” American Vacuum Society 59th International Symposium and Exhibition, Tampa, FL (Oct. 28 – Nov. 2, 2012).

[43] S. Xhurxhi, A. Antony, F. Obst, D. Sidoti, B. Bertoli, T. Kujofsa, S. Cheruku, J. P. Correa, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Design of S-Graded Strain Accommodation Layers for Lattice-Mismatched Semiconductor Devices,” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 7-11, 2012).

[42] J. Raphael, B. Bertoli, and J. E. Ayers, “Equilibrium Strain and Dislocation Density in a Nitride Based Heterostructure,” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 7-11, 2012).

[41] T. Kujofsa and J. E. Ayers, “Theoretical Study of Dislocation Compensation in ZnSySe1-y/GaAs (001) Heterostructures,” Materials Science and Technology Conference, Pittsburgh, PA (Oct. 7-11, 2012).

[40] S. Xhurxhi, K. Koptchaliyiski, F. Obst, D. Sidoti, B. Bertoli, T. Kujofsa, S. Cheruku, J. P. Correa, P. B. Rago, E. N. Suarez, F. C. Jain,  and J. E. Ayers,” S-Graded Buffer Layers for Semiconductor Devices,” Materials Science and Technology Conference, Columbus, OH (Oct. 16-20, 2011).

[39] P. B. Rago and J. E. Ayers,”Dynamical X-Ray Diffraction from Semiconductor Heterostructures with Dislocations,” Materials Science and Technology Conference, Columbus, OH (Oct. 16-20, 2011).

[38] T. Kufofsa, S. Cheruku, B. Outlaw, S. Xhurxhi, F. Obst, D. Sidoti, B. Bertoli, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Plastic Flow and Threading Dislocations in Semiconductor Heterostructures,” Materials Science and Technology Conference, Columbus, OH (Oct. 16-20, 2011).

[37] P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Dynamical X-Ray Diffraction from ZnSySe1-y Multilayers and Superlattices on GaAs (001) Substrates,”  U.S. Workshop on the Physics and Chemistry of II-VI Materials, Chicago, IL (Oct. 4-6, 2011).

[36] S. Cheruku, T. Kujofsa, W. Yu, B. Outlaw, S. Xhurxhi, D. Sidoti, F. Obst, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Critical Layer Thickness in II-VI/GaAs Heterostructures and the Role of Finite Experimental Resolution,” U.S. Workshop on the Physics and Chemistry of II-VI Materials, Chicago, IL (Oct. 4-6, 2011).

[35] T. Kufofsa, S. Cheruku, W. Yu, B. Outlaw, S. Xhurxhi, F. Obst, D. Sidoti, B. Bertoli, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Relaxation Dynamics and Threading Dislocations in ZnSySe1-y/GaAs (001) Heterostructures,” U.S. Workshop on the Physics and Chemistry of II-VI Materials, Chicago, IL (Oct. 4-6, 2011).

[34] S. Xhurxhi, F. Obst, D. Sidoti, B. Bertoli, T. Kujofsa, S. Cheruku, J. P. Correa, P. B. Rago, E. N. Suarez, F. C. Jain, and J. E. Ayers,  “S-Graded Buffer Layers for Semiconductor Devices,” Connecticut Microelectronics and Optoelectronics Symposium, New Haven, CT (March 16, 2011).

[33] T. Kujofsa, S. Cheruku, D. Sidoti, S. Xhurxhi, F. Obst, J. P. Correa, B. Bertoli, P. B. Rago, E. N. Suarez, X. Zhang, P. Li, F. C. Jain, and J. E. Ayers, “Lattice Relaxation by Plastic Flow in ZnSe/GaAs (001),” Connecticut Microelectronics and Optoelectronics Symposium, New Haven, CT (March 16, 2011).

[32] P.-Y. Chan, M. Gogna, E. Suarez, F. Al-Amoody, S. Karmakar, B. I. Miller, J. E. Ayers, and F. C. Jain, “Indium gallium arsenide based non-volatile memory devices with site-specific self-assembled germanium quantum dot gate,” Mat. Res. Soc. Symp. Proc., 1250, 35, Boston, MA (November 2010).

[31] F. Al-Amoody, E. Suarez, A. Rodriguez, W. Huang, J. E. Ayers, and F. Jain, “Embedded ZnCdSe Cladded Quantum Dots Device with Electroluminescent Electrical Characteristics,” U.S. Workshop on the Physics and Chemistry of II-VI Compounds, New Orleans, LA (October 26-28, 2010).

[30] E. Suarez, M. Gogna, F. Al-Amoody, S. Karmakar, J. E. Ayers, E. Heller, and F. Jain, “Radiation Hardened Quantum Dot Nonvolatile memory using ZnS/ZnMgS/ZnS Tunneling Gate Insulator,” U.S. Workshop on the Physics and Chemistry of II-VI Compunds, New Orleans, LA (October 26-28, 2010).

[29] E. Suarez, M. Gogna, F. Al-Amoody, S. Karmakar, J. E. Ayers, E. Heller, and F. C. Jain, “Quantum Dot (QD) Floating Gate Nonvolatile Memories using Lattice-Matched ZnS/ZnMgS/ZnS Gate Insulators,” Connecticut Microlectronics and Optoelectronics Symposium, Storrs, CT (April 7, 2010).

[28] P.-Y. Chan, M. Gogna, E. Suarez, F. Al-Amoody, S. Karmakar, B. I. Miller, J. E. Ayers, and F. C. Jain, “Site-Specific Self-Assembled Germanium Quantum Dot Gate Indium Gallium Arsneide Based Non-Volatile Memory Devices,” Connecticut Microlectronics and Optoelectronics Symposium, Storrs, CT (April 7, 2010).

[27] S. Cheruku, T. Kujofsa, S. Xhurxhi, D. Sidoti, J. P. Correa, B. Bertoli, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Plastic Flow in Semiconductor Heterostructures,” Connecticut Microlectronics and Optoelectronics Symposium, Storrs, CT (April 7, 2010).

[26] B. Bertoli, S. Xhurxhi, D. Sidoti, S. Cheruku, T. Kujofsa, J. P. Correa, E. N. Suarez, F. C. Jain, and J. E. Ayers, “Critical Layer Thickness and Strain Relaxation in Exponentially-Graded Semiconductor Heterostructures,” Connecticut Microlectronics and Optoelectronics Symposium, Storrs, CT (April 7, 2010).

[25] E. Suarez, M. Gogna, F. Alamoody, S. Karmakar, P-Y. Chan, B. Miller, J. Chandy, L. Wang, E. Heller, J. E. Ayers and F. C. Jain, “II-VI Gate Insulators for High Performance Quantum Dot Gate FETs and Nonvolatile Memories,” Connecticut Microelectronics and Optoelectronics Symposium, New Haven, CT (March 11, 2009).

[24] B. Bertoli, E. Suarez, F. C. Jain, and J. E. Ayers, “Strain and dislocation density in a heterostructure with arbitrary compositional grading,” Connecticut Microelectronics and Optoelectronics Symposium, New Haven, CT (March 11, 2009).

[23] J. F. Ocampo, E. Suarez, D. Shah, P. B. Rago, F. C. Jain, and J. E. Ayers, “Asymmetric dislocation densities in graded semiconductor structures,” Connecticut Microelectronics and Optoelectronics Symposium, New Haven, CT (March 11, 2009).

[22] (Invited) J. F. Ocampo, E. Suarez, D. Shah, P. B. Rago, F. C. Jain, and J. E. Ayers, “Overshoot graded layers for defect engineering in heteroepitaxial semiconductor structures,” Materials Science & Technology 2008 Conference, Pittsburgh, PA (October 5-9, 2008).

[21] J. F. Ocampo, E. Suarez, D. Shah, P. B. Rago, F. C. Jain, and J. E. Ayers, “Overshoot graded layers for defect engineering in heteroepitaxial semiconductor structures,” Connecticut Microelectronics and Optoelectronics Symposium, Storrs, CT (April 9, 2008).

[20] A. Rodriguez, P. Li, B. Yarlagadda, F. Papadimitrakopoulos, W. Huang, J. Ayers, and F.  Jain, “ZnCdSe-ZnSe cladded quantum dots using Photoassisted Microwave Plasma (PMP) enhanced metalorganic chemical vapor deposition for lasers and electroluminescent phosphors,” 2006 NSTI Nanotechnology Conference and Trade Show – NSTI Nanotech 2006 Technical Proceedings, Vol. 3, pp. 137-140 (2006).

[19] B. Yarlagadda, A. Rodriguez, P. Li, B. I. Miller, F. C. Jain, and J. E. Ayers, “Elastic Strains in Heteroepitaxial ZnSe1-xTex on InGaAs/InP (001),” 2005 U.S. Workshop on the Physics and Chemistry of II-VI Materials, Cambridge, MA (2005).

[18] P. Li, A. Rodriguez, B. Prakash, R. Shankar, J. E. Ayers, F. C. Jain “Improved interface properties of polyoxide on n-type 4H –SiC by wet oxidation and Ar annealing,” Materials Research Society Fall meeting, Boston, MA (2005).

[17] B. Yarlagadda, A. Rodriguez, P. Li, J. E. Ayers, and F. Jain, “Scan of Azimuthal Mosaic Spread (SAMS): A new method for the characterization of heteroepitaxial layers,” Connecticut Microelectronics and Optoelectronics Symposium, Storrs, CT (March 17, 2005).

[16] B. Yarlagadda, A. Rodriguez, P. Li, J. E. Ayers, and F. C. Jain, “Compositional control and structural properties of ZnSe1-xTex epitaxial films on lattice-matched InGaAs/InP (001) by Photoassisted metal Organic Vapor Phase Epitaxy,” Materials Research Society Spring Meeting, San Francisco, CA (2004).

[15] Rodriguez, J. Shattuck, X. Zhang, P. Li, F. C. Jain, J. E. Ayers, and D. W. Parent, “Photo-assisted MOVPE growth of ZnMgS on (100) Si,” Materials Research Society Fall Meeting, Boston, MA (2001).

[14] X. G. Zhang, A. Rodriguez, P. Li, F. C. Jain, and J. E. Ayers, “Complete removal of threading dislocations from ZnSe on GaAs (001) by patterned heteroepitaxial processing,” Connecticut Microelectronics and Optoelectronics Symposium, Storrs, CT (April 3, 2001).

[13] X. G. Zhang, A. Rodriguez, X. Wang, P. Li, F. C. Jain, and J. E. Ayers, “A Novel Approach for the Complete Removal of Threading Dislocations from ZnSe on GaAs (001),” 2000 U. S. Workshop on the Physics and Chemistry of II-VI Materials, Albuquerque, NM, USA (2000).

[12] X. G. Zhang, A. Rodriguez, P. Li, F. C. Jain, and J. E. Ayers, “A Novel Approach for the Complete Removal of Threading Dislocations from Mismatched Heteroepitaxial Layers,” Materials Research Society Fall Meeting, Boston, MA (2000).

[11] D. W. Parent, A. Rodriguez, P. Li, X. G. Zhang, G. Zhao, J. E. Ayers, and F. C. Jain, “The photoassisted MOVPE growth of ZnSSe using tertiary-butylmercaptan,” 1999 U. S. Workshop on the Physics and Chemistry of II-VI Materials, Las Vegas, NV, USA (1999).

[10] K. Bao, J. E. Ayers, R. Mo, S. Kalisetty, M. Gokhale, J. Robinson, and F. C. Jain, “Compositional control of CdZnSe grown by photoassisted organometallic vapor phase epitaxy,” 8th International Conference on Metal Organic Vapor Phase Epitaxy, Cardiff, Wales, UK (1996).

[9] S. Kalisetty, J. Robinson, X. G. Zhang, J. E. Ayers, and F. C. Jain, “Growth of ZnSSe by photoassisted OMVPE,” 9th International Conference on Vapor Growth and Epitaxy, Vail, CO, USA (1996).

[8] X. G. Zhang, S. Kalisetty, J. Robinson, J. E. Ayers, and F. C. Jain, “Structural Properties of ZnSSe/ZnSe/GaAs (001) heterostructures grown by photoassisted organometallic vapor phase epitaxy,” 1996 U. S. Workshop on the Physics and Chemistry of II-VI Materials, Las Vegas, NV, USA (1996).

[7] D. W.  Parent, X. G. Zhang, S. Kalisetty, W. Zappone, J. Robinson, G. Zhao, J. E. Ayers, and F. C. Jain, “A comparison of ethyl iodide and hydrogen chloride for doping ZnSe grown by photoassisted organometallic vapor phase epitaxy,” 1996 U. S. Workshop on the Physics and Chemistry of II-VI Materials, Las Vegas, NV, USA (1996).

[6] M. R. Gokhale, K. X. Bao, P. D.  Healey, J. E. Ayers, and F. C. Jain, “Role of cadmium in enhancing optical properties and chlorine doping of photoassisted OMVPE-grown ZnSe,” 37th Electronic Materials Conference, Charlottesville, VA, USA (1995).

[5] J. E. Ayers, L. J. Schowalter, and S. K. Ghandhi, “Threading Dislocation Densities in Mismatched Heteroepitaxial Layers,” Materials Research Society Fall 1990 Meeting, Boston, MA, USA (1990).

[4] L. J. Schowalter, J. E. Ayers, S. K. Ghandhi, S. Hashimoto, W. M. Gibson, F. K. LeGoues, and P. A. Claxton, “Strain in epitaxial GaAs on CaF2/Si (111),” Materials Research Society Fall 1989 Meeting, Boston, MA, USA (1989).

[3] Joshua Ladell, John Ayers and John Zola, “Theory and Applications of the Skewed Two-Crystal Monochrocollimator,” American Crystallographic Association Meeting, Philadelphia, PA, USA (1988).

[2] I. B. Bhat, N. R. Taskar, J. Ayers, K. Patel, and S. K. Ghandhi, “CdTe films grown on InSb substrates by organometallic epitaxy,” Materials Research Society Symposia Proceedings, Vol. 90, pp. 471-477 (1987).

[1] I. B. Bhat, N. R. Taskar, K. Patel, J. E. Ayers, S. K. Ghandhi, J. Petruzello, and D. Olego, “Characteristics of OMVPE-grown CdTe and HgCdTe on GaAs,” SPIE, 796, 194 (1987).

 

Theses and Dissertations:

  • J. E. Ayers, “Heteroepitaxy in the Ge-GaAs system,” M. S. Thesis, Rensselaer Polytechnic Institute, Troy, NY, USA (May 1987).
  • J. E. Ayers, “Heteroepitaxy of Mismatched Semiconductors,” Ph. D. Thesis, Rensselaer Polytechnic Institute, Troy, NY, USA (August 1990).

Invention Disclosures:

  • J. E. Ayers, “A new process for the growth of highly-mismatched heteroepitaxial semiconductors, free from threading dislocations,” University of Connecticut Invention Disclosure, April 4, 1997.

Sponsored Research:

[26] “Generalized Kinetic Monte Carlo Model for Si Epitaxy on Surfaces of Arbitrary Orientation,” (PI: John Ayers) Applied Materials, Inc., Feb. 1, 2019 – present, $8,750.

 [25] “Detailed Monte Carlo Model of Silane Epitaxy on (100) Si Surfaces,” (PI: John Ayers) Applied Materials, Inc., Feb. 1, 2018 – Jan. 31, 2019, $8,750.

[24] “Atomistic Modeling of Si Epitaxy on (100) Si Surfaces,” (PI: John Ayers) Applied Materials, Inc., Sept. 23, 2017 – Jan. 31, 2018, $8,750.

[23] “Doping and Orientation Effects in SiGe Strain-Relaxed Buffers for Advanced Integrated Circuit Applications,” (PI: John Ayers) Applied Materials, Inc., Jan. 5, 2017 – Sept. 22, 2017, $8,750.

[22] “Process Considerations for Reduced Threading Dislocations in Strain-Relaxed SiGe Buffers On Si Substrates for Advanced Integrated Circuit Applications,” (PI: John Ayers) Applied Materials, Inc., Dec. 22, 2016 – Jan. 5, 2017, $8,750.

[21] “Modeling of Strain Relaxation and Dislocations in SiGe and Ge Buffers for Advanced Transistors,” (PI: John Ayers) Applied Materials, Inc., June 1, 2016 – Dec. 22, 2016, $8,750.

[20] “Modeling of Strain Relaxed SiGe Buffers for Advanced Transistors,” (PI: John Ayers) Applied Materials, Inc., Nov. 24, 2015 – May 31, 2016, $8,750.

[19] “Strain Relaxed SiGe Buffers for Advanced Transistors,” (PI: John Ayers) Applied Materials, Inc., Sept. 3 – Nov. 23, 2015, $8,750.

[18] “Advanced Processing for CMOS Transistors,” (PI: John Ayers) Applied Materials, Inc., May 1 – Sept. 2, 2015, $8,750.

[17] “Bistability in 500+ GHz Sub-22 nm Quantum Dot Gate InGaAs-InP FETs for Next Generation Analog and Digital Circuits for Advanced Radars and Communication Systems,” (PI: F.C. Jain; Co-PIs:  J. E. Ayers, R. Bansal, J. Chandy, and F. Papadimitrakopoulos), Office of Naval Research, October 1, 2005-September 30, 2008, $420,087, FRS # 524069

[16] “Nanotechnology Undergraduate Education: Development of Introductory and Advanced Theory and Laboratory Courses in Nanoelectronics and Optoelectronics,” (PI: F.C. Jain; Co-PIs: J. E. Ayers, F. Papadimitrakopoulos, R. Magnusson, R. Bansal,  G. Sotzing,  B. Sinkovic,  and Q. Kessel),  National Science Foundation, July 1, 2004-June 30, 2008, $100,000, FRS # 523636

[15] “Reconfigurable Interconnects, 200-500 GHz SiGe and InGaAs-InP Nanochannel FETs, and 1.55 um Quantum Well Laser Modulators on Silicon for Advanced Systems,” (PI:  F. C. Jain, Co-PIs: J. E. Ayers, F. Papadimitrakopoulos, and R. Bansal), Office of Naval Research N000140210883, September 1, 2002-September 30, 2005, $247,000., FRS # 523077.

[14] “Nanochannel FETs and Quantum Dot Based Nonvolatile Memory Cells Using Site-specific and Layer-by-layer Self-Assembly Techniques,” (PI: F. C. Jain, Co-PIs: J. E. Ayers, F. Papadimitrakopoulos, and M. Aindow), National Science Foundation (Nanotechnology Exploratory Research, NER, Initiative), July 1, 2002-June 30, 2005, $93,609, FRS # 523075.

[13] “Advanced SiGe Field-Effect Transistor Design and Processing Technology to Fabricate 10 Gb/s+ Line Interface Circuits for Fiber Optic Communication,” (PI:  F. C. Jain; Co-PIs:  J. E. Ayers, R. Bansal, and F. Papadimitrakopoulos), Connecticut Innovations, Inc., July 1, 2000-June 30, 2004, $290,750., FRS# 630486. 

[12] “Advanced SiGe Field-Effect Transistor Design and Processing Technology to Fabricate 10 Gb/s+ Line Interface Circuits for Fiber Optic Communication,” (PI:  F. C. Jain, Co-PIs:  J. E. Ayers, R. Bansal and F. Papadimitrakopoulos), TranSwitch, July 1,2000-June 30, 2004, $100,000, FRS # 630515.

[11] NER: Nano channel FETs and Quantum dot Based Memory Cells Using Site Specific and Layer-by-Layer Self-Assembly; (PI: F. Jain; Co-PI: J. E. Ayers); NSF; June 1, 2002 – June 30, 2003; $99,999.

[10] Novel site-specific processing of nanopatterns (10-30nm) to fabricate ultrahigh performance SiGe quantum well/wire/dot devices, June 1, 2000- May 31, 2001 (PI: F. Jain, Co-PIs:  J. Ayers and F. Papadimitrakopoulos), UCRF, $18,609.

[9] “Patterned Heteroepitaxial Processing: A New Approach to Mismatched Heteroepitaxy for the Fabrication of High Performance Semiconductor Devices,” (PI: J. E. Ayers, Co-PI: F. C. Jain), NSF, July 1, 1999 – Dec. 31, 2000, $35,312, FRS #521032.

[8] “Reliability Study of Oxidized Deposited Polysilicon (ODP) Gate Oxide for SiC Power MOSFETs,” (PI: J. E. Ayers, Co-PIs: A. F. M. Anwar and F. C. Jain), NSF, July 1, 1999 – May 31, 2001, $38,898, FRS # 521036.

[7] “Development of High Brightness Quantum Dot Based Nanophosphors for Electroluminescent Flat Panel Displays and Illuminators”, Ballistic Missile Defense Organization (Contract N00178-98-C-3035) /E-Lite Technologies Inc., Phase I, $22,000. May 15-November 14, 1998; Fast Track, $11,500. November 14-February 14, 1999; Phase II, April 15-June 30, 2001 (PI: F. C. Jain, Co-PIs: J. E. Ayers and F.  Papadimitrakopoulos), $560,000, FRS # 522418.

[6] “Development of Low Voltage, High Brightness Flexible Electroluminescent Lamps for Display Applications”, CII/Yankee Ingenuity Grant 97G025, $ 200,000, August 12, 1998-August 11, 2000 (PI: F. Jain; Co-PIs: J. E. Ayers and F. Papadimitrakopoulos) $100,000., FRS # 633377.

[5] “MOCVD Reactor for Nanocrystal Growth,” January, 1998-December, (PI: F. C. Jain, Co-PIs: J. E. Ayers and F. Papadimitrakopoulos) UCRF, $14,500. FRS # 440104.

[4] “Electroluminescent flat panel displays using MOCVD grown ZnS and ternary compounds for enhanced blue emission,” (PI: F. C. Jain, Co-PI: J. E. Ayers), UCRF, Jan. 1, 1998 – Dec. 31, 1998, $14,711., FRS # 440922.

[3] “Mismatched heteroepitaxy for the fabrication of high-performance semiconductor devices,” (PI: J. E. Ayers, Co-PI’s: F. C. Jain, A. F. M. Anwar), UCRF, June 1, 1997 – May 31, 1998, $9,407., FRS # 441517.

[2] “Study of Dark-Line Defects in II-VI Heterostructures,” (PI: J. E. Ayers) UCRF, Sept. 1995 – Jan. 1997, $4,480., FRS # 441517.

[1] “New Approaches to the Fabrication of Blue Semiconductor Laser Diodes by Vapor Phase Epitaxy,” (PI: J. E. Ayers) NSF, July 1993 – Jan. 1997, $89,992 ($10,000 matching), FRS # 521714.

 

Current Research Team

Tedi Kujofsa (post-doctoral researcher), Md T. Islam, Kevin Lindstrom, Johanna Raphael, James Wales

 

Former Research Students

Fahad Althowibi, Ansin Antony, Xunde Bao, Brandon Bertoli, Minglei Cai, Andrew Chemistruck, Xinkang Chen, Sushma Cheruku, Juan Pablo Correa, Brandon D’Agostino, Milind Gokhale, Paul Healey, Sarada Kalisetty, Kristian Koptchaliyski, Peng Li, Calvin Lopez, Rihong Mo, Francis Obst, Juan Felipe Ocampo, Brian Outlaw, Paul Rago, Jonathan Reed,  Alvin Sanabria, David Sidoti, Digish Shah, Yifei Song, James Trapp, Christian Wilkie, Sirjan Xhurxhi, Bhanu Yarlagadda, Wei Yu, Xiaoguang Zhang, Guoxing Zhao