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Conference Proceedings

2017

  • W. Sun, Z. Zhang, T. Mohsin, E. Farzana, B. McSkimming, C. Lee, P. Saunier, J. Speck, S. A. Ringel, and A. R. Arehart, “General model for irradiation-induced degradation of GaN HEMTs”, ROCS May 22 - May 25, 2017, Indian Wells, CA

  • W. Sun, S. A. Ringel, and A. R. Arehart, “Ec-0.90 eV trap-induced threshold voltage instability in GaN/Si MISHEMTs”, CS MANTECH May 22 - May 25, 2017, Indian Wells, CA

2016

  • D. J. Chmielewski, K. Galiano, P. Paul, D. Cardwell, S. Carnevale, J. A. Carlin, A. R. Arehart, T. J. Grassman, and S. A. Ringel, “Comparative Study of 2.05 eV AlGaInP and Metamorphic GaInP Materials and Solar Cells Grown by MBE and MOCVD” presented at IEEE International Reliability Physics Symposium, Pasadena CA, April 17-24, 2016.

  • W. Sun, C. Lee, P. Saunier, S. A. Ringel, and A. R. Arehart, “Investigation of trapping effects on AlGaN/GaN HEMT under DC accelerated life testing” presented at IEEE International Reliability Physics Symposium, Pasadena CA, April 17-24, 2016.

  • T. Razzak, C.M. Jackson, S.Sohel, F. Akyol, S. Bajaj, S. Rajan, A.R. Arehart, S.A. Ringel, "Investigation of Deep Levels in High-Al Mole Fraction Al 0.75Ga0.25N" presented at IWN, International Workshop on Nitride Semiconductors, Orlando FL, 2-7 October, 2016.

  • K. Galiano, J. Deitz, S. Carnevale, D. A. Gleason, Z. Zhang, B. McSkimming, J. S. Speck, S. A. Ringel, T. J. Grassman, A. R. Arehart, and J. P. Pelz, "Spatially Correlating the EC-0.57 eV Trap in GaN with Edge Dislocations", presented at IWN, International Workshop on Nitride Semiconductors, Orlando FL, 2-7 October, 2016.

  • A.R. Arehart, W. Sun, K. Galiano, S.Sohel, J.I. Deitz, S.A. Ringel, J.P. Pelz , and T.J. Grassman, "Toward an Understanding of Defects and Device Reliability in GaN Hemts" presented at ECS Prime, Honolulu HI 2-7 October 2016.

  • D.J. Chmielewski, K. Galiano, Pran Paul, D. Cardwell, S. Carnevale, J.A. Carlin, A.R. Arehart, T.J. Grassman, and S.A. Ringel, "Comparative Study of 2.05 eV AlGaInP and Metamorphic GaInP Materials and Solar Cells Grown by MBE and MOCVD", presented at SPRAT the 24th Space Photovoltaic Research and Technology Conference, Cleveland OH 20-22 September 2016.

  • E. Farzana, Z. Zeng, S. Kaun, J. S. Speck, A. R. Arehart and S. A. Ringel, "Characterization of Deep Level Defects in beta-Ga2O3", presented at MRS 58 th Electronic Materials Conference, Delaware NE, 22-24 June 2016.

  • P.  K. Paul, K. Aryal, S. Marsillac, S. A. Ringel, and A. R. Arehart,, “Impact of the Ga/In ratio on defects in Cu(In,Ga)Se2,” 43rd IEEE Photovoltaic Specialists Conference, Portland, OR, June 5-10, 2016.

  • P.  K. Paul, K. Aryal, S. Marsillac, S. A. Ringel, and A. R. Arehart, “Identifying the source of reduced performance in 1-stage-grown Cu(In,Ga)Se2 solar cells,” 43rd IEEE Photovoltaic Specialists Conference, Portland, OR, June 5-10, 2016.

  • D.J. Chmielewski, K. Galiano, P. Paul, D. Cardwell, S. Carnevale, J.A. Carlin, A.R. Arehart, T.J. Grassman, and S.A. Ringel, “Comparative Study of 2.05 eV AlGaInP and Metamorphic GaInP Materials and Solar Cells Grown by MBE and MOCVD,” 43rd IEEE Photovoltaic Specialists Conference, Portland, OR, June 5-10, 2016.

  • J. I. Deitz, D. W. McComb, and T. J. Grassman, “Probing the electronic structure at the heterovalent GaP/Si interface using electron energy-loss spectroscopy,” in 2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC), 1545–1548, 5-10 June 2016

  • T. J. Grassman, D. J. Chmielewski, J. A. Carlin, and S. A. Ringel, “Development of epitaxial 2- and 3-junction III-V/Si solar cells,” in 2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC), 2036–2039, 5-10 June 2016

2015

  • A. Sasikumar, Z. Zhang, P. Kumar, E. X. Zhang, D. M. Fleetwood, R. D. Schrimpf, P. Saunier, C. Lee, S. A. Ringel, A. R. Arehar “Proton irradiation-induced traps causing VT instabilities and RF degradation in GaN HEMTs”, in IEEE Intl. Reliab. Phys. Symp., 2015.

  • A. R. Arehart, A. Sasikumar, Z. Zhang, P. Kumar, B. Poling, G. D. Via, E. Heller, D. M. Fleetwood, R. D. Schrimpf, P. Saunier, C. Lee, and Steven A. Ringel, “Comparison of Irradiation and Electrical Stressors on AlGaN/GaN HEMT Reliability”, in Govt. Microcircuit Appl. Critical Tech. Conf. (GOMACTech), 2015.

2014

  • J. Deitz, S. Carnevale, M. De Graef, Y. N. Picard, S. A. Ringel, T. J. Grassman, D. W. McComb, "Using Electron Channeling Contrast Imaging for Misfit Dislocation Characterization in Heteroepitaxial III-V/Si Thin Films," Microscopy and Microanalysis 20(S3), 2014, pp. 552-553.

  • S. D. Carnevale, J. I. Deitz, J. A. Carlin, Y. N. Picard, M. De Graef, S. A. Ringel, T. J. Grassman, “Rapid Characterization of Extended Defects in III-V/Si by Electron Channeling Contrast Imaging,” Proc. 40th IEEE Photovoltaic Specialists Conference, 2014, pp. 2800.

  • J. S. Speck, Z. Zhang, A. R. Arehart, E. Cinkilic, J. Chen, E. X. Zhang, Y. S. Puzyrev, C. X. Zhang, M. W. McCurdy, S. T. Pantelides, B. McSkimming, S. W. Kaun, E. C. H. Kyle, D. M. Fleetwood, R. D. Schrimpf, S. A. Ringel, “Proton Irradiation in Bulk GaN Layers and Nitride-based HEMT Devices,” in Govt. Microcircuit Appl. Critical Tech. Conf. (GOMACTech) 2014.

  • C. Ratcliff, T. J. Grassman, J. A. Carlin, D. J. Chmielewski and S. A. Ringel, "Ga-rich GaxIn1-xP solar cells on si with 1.95 eV bandgap for ideal III-V/Si photovoltaics," in Proceedings of SPIE, 2014, pp. 898118.

  • A. Sasikumar, A. R. Arehart, S. W. Kaun, J. Chen, E. X. Zhang, D. M. Fleetwood, R. D. Schrimpf, J. S. Speck and S. A. Ringel, "Defects in GaN based transistors," in Proceedings of SPIE, 2014, pp. 89861C.

  • A. Sasikumar, D. W. Cardwell, A. R. Arehart, J. Lu, S. W. Kaun, S. Keller, U. K. Mishra, J. S. Speck, J. P. Pelz and S. A. Ringel, "Toward a physical understanding of the reliability-limiting E-C-0.57 eV trap in GaN HEMTs," in International Reliability Physics Symposium, 2014.

2013

  • I. Al Mansouri, S. Bremner, A. Ho-Baillie, H. Mehrvarz, X. Hao, G. Conibeer, M. A. Green, T. J. Grassman, J. A. Carlin and S. A. Ringel, "Design of bottom silicon solar cell for multijunction devices," in 39th IEEE Photovoltaic Specialists Conference (PVSC), 2013, pp. 3310-3314.

  • D. J. Chmielewski, T. J. Grassman, A. M. Carlin, J. Carlin, A. Speelman and S. A. Ringel, "Metamorphic tunnel junctions for high efficiency III-V/IV multi-junction solar cell technology," in IEEE Photovoltaic Specialists Conference, 2013, pp. 882-885.

  • T. J. Grassman, J. A. Carlin, C. Ratcliff, D. J. Chmielewski and S. A. Ringel, "Epitaxially-grown metamorphic GaAsP/Si dual-junction solar cells," in IEEE Photovoltaic Specialists Conference, 2013, pp. 149-153.

  • T. J. Grassman, D. B. Shah, J. A. Carlin and S. A. Ringel, "Exploration of epitaxial quantum dots within wide band gap metamorphic host materials for intermediate band solar cells," in IEEE Photovoltaic Specialists Conference, 2013, pp. 284-287.

  • S. A. Ringel, J. A. Carlin, T. J. Grassman, B. Galiana, A. M. Carlin, C. Ratcliff, D. Chmielewski, L. Yang, M. J. Mills, A. Mansouri, S. P. Bremner, A. Ho-Baillie, X. Hao, H. Mehrvarz, G. Conibeer and M. A. Green, "Ideal GaP/Si heterostructures grown by MOCVD: III-V/Active-si subcells, multijuntions, and MBE-to-MOCVD III-V/Si interface science," in IEEE Photovoltaic Specialists Conference, 2013, pp. 3383-3388.

2012

  • A. M. Carlin, T. J. Grassman, M. R. Brenner, J. Grandal, C. Ratcliff, L. Yang, M. Mills, P. Sharma, E. A. Fitzgerald and S. A. Ringel, "Lattice-matched GaP/SiGe virtual substrates for low-dislocation density GaInP/GaAsP/Si solar cells," in 2012, pp. 918-921.

  • J. Grandal, T. J. Grassman, A. M. Carlin, M. R. Brenner, B. Galiana, J. A. Carlin, L. Yang, M. J. Mills and S. A. Ringel, "Growth and characterization of InGaAs quantum dots on metamorphic GaAsP templates by molecular beam epitaxy," in 38th IEEE Photovoltaic Specialists Conference (PVSC), 2012, pp. 1783-1787.

  • T. J. Grassman, C. Ratcliff, A. M. Carlin, J. A. Carlin, L. -. Yang, M. J. Mills and S. A. Ringel, "III-V/GaP epitaxy on si for advanced photovoltaics and green light emitters," in ECS Transactions, 2012, pp. 321-332.

  • T. J. Grassman, A. M. Carlin, J. Grandal, C. Ratcliff, L. Yang, M. J. Mills and S. A. Ringel, "Spectrum-optimized si-based III-V multijunction photovoltaics," in Proceedings of SPIE, 2012, pp. 82560R.

  • A. Sasikumar, A. Arehart, S. A. Ringel, S. Kaun, M. H. Wong, U. K. Mishra and J. S. Speck, "Direct correlation between specific trap formation and electric stress-induced degradation in MBE-grown AlGaN/GaN HEMTs," in IEEE International Reliability Physics Symposium (IRPS), 2012, .

  • K. Swaminathan, T. J. Grassman, L. -. Yang, D. Chmielewski, M. Mills and S. A. Ringel, "Impact of threading dislocation density on metamorphic InxGa1-xAs and InzGa1-zP p-i-n photodetectors on GaAs," in Proceedings of SPIE, 2012, pp. 82571A.

2010

  • A. R. Arehart, M. R. Brenner, Z. Zhang, K. Swaminathan and S. A. Ringel, "Traps in algainp materials and devices lattice matched to gaas for multi-junction solar cells," in IEEE Photovoltaic Specialists Conference, 2010, pp. 1999-2001.

  • A. R. Arehart, A. Sasikumar, G. D. Via, B. Winningham, B. Poling, E. Heller and S. A. Ringel, "Spatially-discriminating trap characterization methods for HEMTs and their application to RF-stressed AlGaN/GaN HEMTs," in International Electron Devices Meeting, 2010, .

  • T. J. Grassman, A. M. Carlin and S. A. Ringel, "Metamorphic gaasp and ingap photovoltaic materials on si for high-efficiency iii-V/si multijunction solar cells," in IEEE Photovoltaic Specialists Conference, 2010, pp. 2029-2033.

  • J. H. Warner, S. I. Maximenk, S. R. Messenger, R. J. Walters, S. A. Ringel, M. R. Brenner and A. M. Carlin, "Electrical characterization of electron and proton-induced defects in P+n gaas photodiodes: Ebic study," in IEEE Photovoltaic Specialists Conference, 2010, pp. 002646.

2009

  • X. J. Chen, H. J. Barnaby, J. H. Warner, S. R. Messenger, R. J. Walters, S. A. Ringel and J. Park, "Non-linear behaviors of dark current slope in p(+)n gaas solar cells following proton irradiations," in IEEE Photovoltaic Specialists Conference, 2009, pp. 1532-1537.

  • T. J. Grassman, M. R. Brenner, A. M. Carlin, S. Rajagopalan, R. Unocic, R. Dehoff, M. Mills, H. Fraser and S. A. Ringel, "Toward metamorphic multijunction GaAsP/Si photovoltaics grown on optimized GaP/Si virtual substrates using anion-graded GaAs(y)P(1-y) buffers," in IEEE Photovoltaic Specialists Conference, 2009, pp. 2011-2016.

  • T. K. Ng, S. F. Yoon, K. H. Tan, W. K. Loke, S. Wicaksono, K. L. Lew, K. P. Chen, E. A. Fitzgerald, A. J. Pitera, S. A. Ringel, A. M. Carlin and M. Gonzalez, "1ev gan(x)as(1-x-y)sb(y) material for lattice-matched iii-v solar cell implementation on gaas and ge," in IEEE Photovoltaic Specialists Conference, 2009, pp. 1130-1134.

2008

  • D. M. Wilt, A. T. Pal, S. A. Ringel, E. A. Fitzgerald, P. P. Jenkins and R. Walters, "FINAL RESULTS FROM THE MISSE5 GaAs ON si SOLAR CELL EXPERIMENT," in IEEE Photovoltaic Specialists Conference, 2008, pp. 2078-2081.

2007

  • A. Armstrong, A. Chakraborty, J. S. Speck, S. P. DenBaars, U. K. Mishra and S. A. Ringel, "Characterization and discrimination of AlGaN- and GaN-related deep levels in AlGaN/GaN heterostructures," in Aip Conference Proceedings, 2007, pp. 223-224.

  • D. Liu, M. Hudait, Y. Lin, S. A. Ringel and W. Lu, "80nm In0.52Al0.48As/In0.53Ga0.47As/InAs0.3P0.7 composite channel HEMT with an f(T) of 280GHz," in International Semiconductor Device Research Symposium, College Pk, MD, 2007, pp. 549.

2006

  • K. Lee, B. VanMil, M. Luo, T. H. Myers, A. Armstrong, S. A. Ringel, M. Rummukainen and K. Saarinen, "Compensation in be-doped gallium nitride grown using molecular beam epitaxy," in Materials Research Society Symposium Proceedings, 2006, pp. 729-734.

  • D. M. Wilt, S. A. Ringel, E. A. Fitzgerald and P. P. Jenkins, "Preliminary on-orbit performance data from GaAs on si solar cells aboard misses," in 4th World Conference on Photovoltaic Energy Conversion, Waikoloa, HI, 2006, pp. 1918.

2005

  • A. Armstrong, D. Green, A. Arehart, U. Mishra, J. Speck and S. Ringel, "Carbon-related deep states in compensated n-type and semi-insulating GaN : C and their influence on yellow luminescence," in Materials Research Society Symposium Proceedings, 2005, pp. 311-316.

  • D. Liu, M. Hudait, Y. Lin, H. Kim, S. A. Ringel and W. Lu, "0.25 mu m in(0.52)A1(0.48)As/In(0.53)ga(0.47)As/InAs(0.3)P(0.7) composite channel HEMTs with an f(T) of 115GHz," in Asia Pacific Microwave Conference-Proceedings, Suzhou, China, 2005, pp. 829.

  • M. Lueck, M. Gonzalez, O. Kwon, C. Andre and S. Ringel, "Impact of annealing and V : III ratio on properties of MBE grown wide-bandgap AIGaInP materials and solar cells," in Ieee Photovoltaic Specialists Conference, 2005, pp. 711-714.

  • S. Ringel, C. Andre, E. Fitzgerald, A. Pitera and D. Wilt, "Multi-junction III-V photovoltaics on lattice-engineered si sustrates," in Ieee Photovoltaic Specialists Conference, 2005, pp. 567-570.

  • S. Ringel, C. Andre, M. Lueck, D. Isaacson, A. Pitera, E. Fitzgerald and D. Wilt, "III-V multi-junction materials and solar cells on engineered SiGe/Si substrates," in Materials Research Society Symposium Proceedings, 2005, pp. 211-222.

  • C. Tivarus, K. Park, M. Hudait, S. Ringel and J. Pelz, "Nanoscale characterization of metal/semiconductor nanocontacts," in Aip Conference Proceedings, 2005, pp. 280-284.

  • D. Wilt, A. Pal, N. Prokop, S. Ringel, C. Andre, M. Smith, D. Scheiman, P. Jenkins, W. Maurer, B. McElroy and E. Fitzgerald, "Thermal cycle testing of GaAs on si and metamorphic tandem on si solar cells," in Ieee Photovoltaic Specialists Conference, 2005, pp. 571-574.

2004

  • A. Armstrong, A. Arehart, B. Moran, S. DenBaars, U. Mishra, J. Speck and S. Ringel, "Impact of growth pressure on defects in GaN grown by metalorganic chemical vapor deposition," in 30th International Symposium on Compound Semiconductors, San Diego, CA, 2004, pp. 48.

  • O. Kwon, J. Boeckl, M. Lee, A. Pitera, E. Fitzgerald and S. Ringel, "Growth and properties of AlGaInP resonant cavity light emitting diodes (RCLEDs) on Ge/SiGe/Si substrates," in Materials Research Society Symposium Proceedings, 2004, pp. 161-166.

2003

  • A. Arehart, C. Poblenz, B. Heying, J. Speck, U. Mishra, S. DenBaars and S. Ringel, "Influence of growth parameters on the deep level spectrum in MBE-grown n-GaN," in Materials Research Society Symposium Proceedings, 2003, pp. 735-740.

  • A. Armstrong, A. Arehart, S. Ringel, B. Moran, S. DenBaars, U. Mishra and J. Speck, "Identification of carbon-related bandgap states in GaN grown by MOCVD," in Materials Research Society Symposium Proceedings, 2003, pp. 509-514.

  • S. Ringel, C. Andre, M. Hudait, D. Wilt, E. Clark, A. Pitera, M. Lee, E. Fitzgerald, M. Carroll, M. Erdtmann, E. Carlin and B. Keyes, "Toward high performance N/P GaAs solar cells grown on low dislocation density p-type sige substrates," in 3rd World Conference on Photovoltaic Energy Conversion, Osaka, Japan, 2003, pp. 615.

2002

  • C. Andre, A. Khan, M. Gonzalez, M. Hudait, E. Fitzgerald, J. Carlin, M. Currie, C. Leitz, T. Langdo, E. Clark, D. Wilt and S. Ringel, "Impact of threading dislocations on both n/p and p/n single junction GaAs cells grown on Ge/SiGe/Si substrates," in 29th IEEE Photovoltaic Specialists Conference, NEW ORLEANS, LA, 2002, pp. 1046.

  • M. Hudait, Y. Lin, C. Andre, P. Sinha, C. Tivarus, J. Pelz, D. Wilt and S. Ringel, "Relaxed InAsP layers grown on step graded InAsP buffers by solid source MBE," in Materials Research Society Symposium Proceedings, 2002, pp. 287-292.

  • R. Kaplar, S. Ringel, S. Kurtz, A. Allerman and J. Klem, "Comparison of deep level spectra of MBE- and MOCVD-grown InGaAsN," in Materials Research Society Symposium Proceedings, 2002, pp. 403-408.

2000

  • J. Carlin, M. Hudait, S. Ringel, D. Wilt, E. Clark, C. Leitz, M. Currie, T. Langdo and E. Fitzgerald, "High efficiency GaAs-on-si solar cells with high V-oc using graded GeSi buffers," in Ieee Photovoltaic Specialists Conference, 2000, pp. 1006-1011.

  • A. Hierro, J. Boeckl, S. Ringel, M. Hansen, U. Mishra, S. DenBaars, J. Speck and D. Look, "Detection and identification of deep levels in n-GaN," in International Workshop on Nitride Semiconductors (IWN 2000), Nagoya, Japan, 2000, pp. 462.

1999

  • M. Clevenger, C. Murray, S. Ringel, R. Sacks, L. Qin, G. Charache and D. Depoy, "Optical properties of thin semiconductor device structures with reflective back-surface layers," in Aip Conference Proceedings, 1999, pp. 327-334.

  • A. Hierro, D. Kwon, S. Ringel, L. Brillson, A. Young and A. Franciosi, "Deep level characterization of interface-engineered ZnSe layers grown by molecular beam epitaxy on GaAs," in Materials Research Society Symposium Proceedings, 1999, pp. 77-82.

  • D. Kwon, R. Kaplar, J. Boeckl, S. Ringel, A. Allerman, S. Kurtz and E. Jones, "Keep level defect studies in MOCVD-grown InxGa1-xAs1-yNy films lattice-matched to GaAs," in Materials Research Society Symposium Proceedings, 1999, pp. 59-64.

  • S. Ringel, J. Carlin, R. Sieg, J. Boeckl and E. Fitzgerald, "Highly-controlled GaAs/Ge interfaces and implications for III-V optoelectronic integration onto group IV substrates," in 1st International Workshop on Lattice-Mismatched and Heterovalent Thin Film Epitaxy, Castelvecchio Pas, Italy, 1999, pp. 96.

  • S. Ringel, R. Sacks, L. Qin, M. Clevenger and C. Murray, "Growth and properties of InGaAs/FeAl/InAlAs/InP heterostructures for buried reflector/interconnect applications in InGaAs thermophotovoltaic devices," in Aip Conference Proceedings, 1999, pp. 142-151.

1998

  • R. Hoffman, N. Fatemi, V. Weizer, P. Jenkins, M. Stan, S. Ringel, R. Sieg, D. Scheiman, D. Wilt and D. Brinker, "The effect of the zn interstitial defect on the performance of p/n InP solar cells," in Materials Research Society Symposium Proceedings, 1998, pp. 235-240.

1997

  • B. Chatterjee, S. Ringel and R. Hoffman, "Hydrogen-interstitial zn defect complexes and their effects on the device characteristics of heteroepitaxial p(+)n InP cell structures," in Ieee Photovoltaic Specialists Conference, 1997, pp. 907-910.

  • R. Hoffman, N. Fatemi, P. Jenkins, V. Weizer, M. Stan, S. Ringel, D. Scheiman, D. Wilt, D. Brinker, R. Walters and S. Messenger, "Improved performance of p/n InP solar cells," in Ieee Photovoltaic Specialists Conference, 1997, pp. 815-818.

  • S. Ringel and P. Grillot, "Dislocation interactions and their impact on electrical properties of GeSi-based heterostructures," in Materials Research Society Symposium Proceedings, 1997, pp. 313-324.

  • S. Ringel, R. Sieg, S. Ting and E. Fitzgerald, "Anti-phase domain-free GaAs on ge substrates grown by molecular beam epitaxy for space solar cell applications," in Ieee Photovoltaic Specialists Conference, 1997, pp. 793-798.

1996

  • B. Chatterjee, S. Ringel and R. Hoffman, "A comparison of hydrogen passivation in heteroepitaxial n(+)p and p(+)n solar cells," in 25th IEEE Photovoltaic Specialists Conference, Washington, DC, 1996, pp. 182.

  • R. Hoffman, N. Fatemi, P. Jenkins, D. Scheiman, S. Ringel, W. Davis, V. Weizer, D. Wilt and D. Brinker, "Development of high efficiency p(+)/n InP solar cells for hetero-epitaxial applications," in 25th IEEE Photovoltaic Specialists Conference, Washington, DC, 1996, pp. 174.

1994

  • B. Chatterjee, S. A. Ringel, R. Sieg, I. Weinberg and R. Hoffman, "Deep-level characterization and passivation in heteroepitaxial InP," in Materials Research Society Symposium Proceedings, Boston, MA, 1994, pp. 125-130.

  • P. N. Grillot, S. A. Ringel, G. P. Watson, E. A. Fitzgerald and Y. H. Xie, "Electronic characterization of dislocations in rtcvd germanium-silicon silicon grown by graded layer epitaxy," in Materials Research Society Symposium Proceedings, 1994, pp. 159-164.

  • S. A. Ringel, B. Chatterjee, R. M. Sieg and E. V. Schnetzer, "Material quality and dislocation trapping in hydrogen passivated heteroepitaxial InP/GaAs and InP/Ge solar cells," in Ieee Photovoltaic Specialists Conference, 1994, pp. 2204-2207.

1991

  • A. ROHATGI, S. RINGEL, R. SUDHARSANAN and H. CHOU, "An improved understanding of efficiency limiting defects in polycrystalline Cdte/cds solar-cells," in Ieee Photovoltaic Specialists Conference, LAS VEGAS, NV, 1991, pp. 966.

1988

  • S. A. Ringel and A. Rohatgi, "Material quality and design optimization for high-efficiency gaas solar-cells," in Ieee Photovoltaic Specialists Conference, LAS VEGAS, NV, 1988, pp. 671.

  • A. ROHATGI, R. SUDHARSANAN, S. RINGEL, P. MEYERS and C. LIU, "Wide bandgap thin-film solar-cells from cdte alloys," in Ieee Photovoltaic Specialists Conference, LAS VEGAS, NV, 1988, pp. 1481.