Andrew Gerger

Education History

• BS, Materials Science and Engineering, University of Florida
• MS, Materials Science and Engineering, University of Florida
• PHD, Materials Science and Engineering, University of Florida

Work Experience

Senior Professional Staff, JHU Applied Physics Laboratory

Publications

Gila, B. P.; Onstine, A. H.; Hlad, M.; Gerger, A.; Herrero, A.; Allums, K. K.; Stodilka, D.; Jang, S.; Kang, B.; Anderson, T.; Abernathy, C. R.; Ren, F.; Pearton, S. J. Novel oxides and reliability for the passivation of AlGaN/GaN high electron mobility transistor. Proceedings – Electrochemical Society (2005), 2005-04(State-of-the-Art Program on Compound Semiconductors (SOTAPOCS XLII) and Processes at the Compound-Semiconductor/Solution Interface), 247-261.

Gila, B. P.; Hlad, M.; Anderson, T.; Chen, J.-J.; Allums, K. K.; Gerger, A.; Herrero, A.; Jang, S.; Kang, B.; Abernathy, C. R.; Ren, F.; Pearton, S. J. Oxide dielectrics for reliable passivation of AlGaN/GaN HEMTs and insulated gates. ECS Transactions (2006), 3(5, State-of-the-Art Program on Compound Semiconductors 45 (SOTAPOCS 45) and Wide Bandgap Semiconductor Materials and Devices 7), 141-150.

Stodilka, D. O.; Gerger, A. P.; Hlad, M.; Kumar, P.; Gila, B. P.; Singh, R.; Abernathy, C. R.; Pearton, S. J.; Ren, F. Alternative magnesium calcium oxide gate dielectric for silicon carbide MOS application. Materials Research Society Symposium Proceedings (2006), 911(Silicon Carbide 2006–Materials, Processing and Devices), 347-352.

Wang, Hung-Ta; Kang, B. S.; Ren, F.; Herrero, A.; Gerger, A. M.; Gila, B. P.; Pearton, S. J.; Shen, H.; LaRoche, Jeffery R.; Smith, Kurt V. Thermal Stability of Au Schottky Diodes on GaAs Deposited at Either 77 or 300 K. Journal of the Electrochemical Society (2006), 153(9), G787-G790.

Wang, Hung-Ta; Jang, S.; Anderson, T.; Chen, J. J.; Kang, B. S.; Ren, F.; Herrero, A.; Gerger, A. M.; Gila, B. P.; Pearton, S. J.; Shen, H.; LaRoche, Jeffrey R.; Smith, Kurt V. Improved Au Schottky contacts on GaAs using cryogenic metal deposition. Journal of Vacuum Science & Technology, B: Microelectronics and Nanometer Structures–Processing, Measurement, and Phenomena (2006), 24(4), 1799-1802.

Gila, B. P.; Thaler, G. T.; Onstine, A. H.; Hlad, M.; Gerger, A.; Herrero, A.; Allums, K. K.; Stodilka, D.; Jang, S.; Kang, B.; Anderson, T.; Abernathy, C. R.; Ren, F.; Pearton, S. J. Novel dielectrics for gate oxides and surface passivation on GaN. Solid-State Electronics (2006), 50(6), 1016-1023.

Chen, J.-J.; Gila, B. P.; Hlad, M.; Gerger, A.; Ren, F.; Abernathy, C. R.; Pearton, S. J. Band offsets in the Sc2O3/GaN heterojunction system. Applied Physics Letters (2006), 88(14), 142115/1-142115/3.

Chen, J.-J.; Gila, B. P.; Hlad, M.; Gerger, A.; Ren, F.; Abernathy, C. R.; Pearton, S. J. Determination of MgO/GaN heterojunction band offsets by x-ray photoelectron spectroscopy. Applied Physics Letters (2006), 88(4), 042113/1-042113/3.

Polyakov, A. Y.; Smirnov, N. B.; Gila, B. P.; Hlad, M.; Gerger, A. P.; Abernathy, C. R.; Pearton, S. J. Studies of interface states in Sc2O3/GaN, MgO/GaN, and MgScO/GaN structures. Journal of the Electrochemical Society (2007), 154(2), H115-H118.

Allums, K. K.; Hlad, M.; Gerger, A. P.; Gila, B. P.; Abernathy, C. R.; Pearton, S. J.; Ren, F.; Dwivedi, R.; Fogarty, T. N.; Wilkins, R. Effect of proton irradiation on interface state density in Sc2O3/GaN and Sc2O3/MgO/GaN diodes. Journal of Electronic Materials (2007), 36(4), 519-523.

Chen, J.-J.; Hlad, M.; Gerger, A. P.; Gila, B. P.; Ren, F.; Abernathy, C. R.; Pearton, S. J. Band offsets in the Mg0.5Ca0.5O/GaN heterostructure system. Journal of Electronic Materials (2007), 36(4), 368-372.

Herrero, Andrew M.; Gerger, A. M.; Gila, B. P.; Pearton, S. J.; Wang, Hung-Ta; Jang, S.; Anderson, T.; Chen, J. J.; Kang, B. S.; Ren, F.; Shen, H.; LaRoche, Jeffrey R.; Smith, Kurt V. Interfacial differences in enhanced Schottky barrier height Au/n-GaAs diodes deposited at 77 K. Applied Surface Science (2007), 253(6), 3298-3302.

Jang, J. H.; Phen, M. S.; Gerger, A.; Jones, K. S.; Hansen, J. L.; Larsen, A. N.; Craciun, V. Structural characterization of strained silicon grown on a SiGe buffer layer. Semiconductor Science and Technology (2008), 23(3), 035012/1-035012/5.

Stewart, A. D.; Gerger, A.; Gila, B. P.; Abernathy, C. R.; Pearton, S. J. Determination of Sm2O3/GaAs heterojunction band offsets by X-ray photoelectron spectroscopy. Applied Physics Letters (2008), 92(15), 153511/1-153511/3.

Chang, C. Y., Wang, Y. L., Gila, B. P., Gerger, A. P., Pearton, S. J., Lo, C. F., … & Han, J. (2009). Effect of gate orientation on dc characteristics of Si-doped, nonpolar AlGaN/GaN metal-oxide semiconductor high electron mobility transistors. Applied physics letters, 95(8), 082110-082110.

Herrero, A. M., Gila, B. P., Gerger, A., Scheuermann, A., Davies, R., Abernathy, C. R., … & Ren, F. (2009). Environmental stability of candidate dielectrics for GaN-based device applications. Journal of Applied Physics, 106(7), 074105-074105.

Gerger, Andrew Phillip. Growth and characterization of gallium nitride on lattice-matched magnesium calcium oxide. Dissertation, University of Florida. ProQuest, 2009. (Publication No.AAI3385927.)

Wang, Y., Kerestes, C., Wang, L., Gerger, A., Lochtefeld, A., Opila, R., & Barnett, A. (2011, June). Design, fabrication, characterization and improvement of Ge: Si solar cell below Si solar cell in a multi-junction solar cell system. In Photovoltaic Specialists Conference (PVSC), 2011 37th IEEE (pp. 000290-000294). IEEE.

Wang, L., Wang, Y., Gerger, A., Lochtefeld, A., Shreve, K., & Barnett, A. (2011, June). Three terminal Si-Si: Ge solar cells. In Photovoltaic Specialists Conference (PVSC), 2011 37th IEEE (pp. 000286-000289). IEEE.

Schmieder, K. J., Gerger, A., Diaz, M., Pulwin, Z., Ebert, C., Lochtefeld, A., … & Barnett, A. (2012, June). Analysis of tandem III–V/SiGe devices grown on Si. In Photovoltaic Specialists Conference (PVSC), 2012 38th IEEE (pp. 000968-000973). IEEE.

Ruiying Hao; Murcia, C.P.; Leitz, C.; Gerger, A.P.; Lochtefeld, A.; Curtin, M.; Shreve, K.; Opila, R.; Barnett, A., Investigating Voltage as a Function of the Reduced Junction Area for Thin Silicon Solar Cells That Utilize Epitaxial Lateral Overgrowth, Photovoltaics, IEEE Journal of , vol.3, no.1, pp.119,124, Jan. 2013

Wang, Y., Gerger, A., Lochtefeld, A., Wang, L., Kerestes, C., Opila, R., & Barnett, A. (2013). Design, fabrication and analysis of germanium: silicon solar cell in a multi-junction concentrator system. Solar Energy Materials and Solar Cells, 108, 146-155.

Li, D., Zhao, X., Diaz, M., Conrad, B., Wang, L., Soeriyadi, A.H., Gerger, A., Lochtefeld, A., Barnett, A. and Perez-Wurfl, I., 2015, June. Optical and electrical analysis of graded buffer layers in III-V/SiGe on silicon tandem solar cells. In Photovoltaic Specialist Conference (PVSC), 2015 IEEE 42nd (pp. 1-3). IEEE.

Schmieder, K.J., Gerger, A., Diaz, M., Pulwin, Z., Curtin, M., Wang, L., Ebert, C., Lochtefeld, A., Opila, R.L. and Barnett, A., 2015. GaAsP on SiGe/Si material quality improvements with in-situ stress sensor and resulting tandem device performance. Materials Science in Semiconductor Processing, 39, pp.614-620.

Diaz, M., Wang, L., Li, D., Zhao, X., Conrad, B., Soeriyadi, A., Gerger, A., Lochtefeld, A., Ebert, C., Opila, R. and Perez-Wurfl, I., 2015. Tandem GaAsP/SiGe on Si solar cells. Solar Energy Materials and Solar Cells, 143, pp.113-119.

Wang, L., Diaz, M., Conrad, B., Zhao, X., Li, D., Soeriyadi, A., Gerger, A., Lochtefeld, A., Ebert, C., Perez-Wurfl, I. and Barnett, A., 2015. Material and Device Improvement of GaAsP Top Solar Cells for GaAsP/SiGe Tandem Solar Cells Grown on Si Substrates. Photovoltaics, IEEE Journal of, 5(6), pp.1800-1804.

Wang, L., Han, J., Ji, J., Lennon, A., Lochtefeld, A., Gerger, A., Carroll, M., Teng, P., Opila, R. and Barnett10, A., Light Trapping in an 18 um Silicon Solar Cell with a Current Density of 34.5 mA/cm 2.

Wang, L., Han, J., Lochtefeld, A., Gerger, A. and Barnett, A., 2015. Analysis of Losses in Open Circuit Voltage for an 18-μm Silicon Solar Cell. Applied Sciences, 5(4), pp.682-694.

Wang, L., Conrad, B., Soeriyadi, A., Zhao, X., Li, D., Diaz, M., Lochtefeld, A., Gerger, A., Perez-Wurfl, I. and Barnett, A., 2016. Current matched three-terminal dual junction GaAsP/SiGe tandem solar cell on Si. Solar Energy Materials and Solar Cells, 146, pp.80-86.

Wang, L., Conrad, B., Soeriyadi, A., Diaz, M., Zhao, X., Li, D., Lochtefeld, A., Gerger, A., Ebert, C., Perez-Wurfl, I. and Barnett, A., 2015, June. Current matched GaAsP/SiGe tandem device on Si over 20% efficiency under indoor measurement. In Photovoltaic Specialist Conference (PVSC), 2015 IEEE 42nd (pp. 1-4). IEEE.

Zhao, X., Li, D., Conrad, B., Wang, L., Soeriyadi, A.H., Diaz, M., Lochtefeld, A., Gerger, A., Perez-Wurfl, I. and Barnett, A., 2015, June. Short ciruit current improvement of SiGe solar cell in a gallium arsenide phosphide-silicon germanium dual junction solar cell on Si substrate. In Photovoltaic Specialist Conference (PVSC), 2015 IEEE 42nd (pp. 1-3). IEEE.

Li, D., Zhao, X., Gerger, A., Opila, R., Wang, L., Conrad, B., Soeriyadi, A.H., Diaz, M., Lochtefeld, A., Barnett, A. and Perez-Wurfl, I., 2015. Optical constants of silicon germanium films grown on silicon substrates. Solar Energy Materials and Solar Cells, 140, pp.69-76.

Conrad, B., Zhao, X., Li, D., Wang, L., Diaz, M., Soeriyadi, A., Lochtefeld, A., Gerger, A., Barnett, A. and Perez-Wurfl, I., 2016. Window optimization enabling broadband double-layer antireflection coating for GaAsP/SiGe tandem on silicon. Solar Energy, 127, pp.216-222.

Gerger, A., Sharps, P., Stall, R., Sulyma, C., de Zetter, K., Johnson, P. and Crist, K., 2015, June. Development and implementation of unique testing methods for the Solar Probe Plus array. In Photovoltaic Specialist Conference (PVSC), 2015 IEEE 42nd (pp. 1-4). IEEE.

Soeriyadi, A.H., Conrad, B., Zhao, X., Li, D., Wang, L., Lochtefeld, A., Gerger, A., Perez-Wurfl, I. and Barnett, A., 2016. Increased Spectrum Utilization with GaAsP/SiGe Solar Cells Grown on Silicon Substrates. MRS Advances, pp.1-6.

Wang, L., Li, D., Zhao, X., Conrad, B., Diaz, M., Soeriyadi, A., Lochtefeld, A., Gerger, A., Perez‐Wurfl, I. and Barnett, A., 2016. Current and efficiency improvement for a GaAsP/SiGe on Si tandem solar cell device achieved by light trapping techniques. physica status solidi (RRL)-Rapid Research Letters, 10(8), pp.596-599.

Yaung, K.N., Kirnstoetter, S., Faucher, J., Gerger, A., Lochtefeld, A., Barnett, A. and Lee, M.L., 2016. Threading dislocation density characterization in III–V photovoltaic materials by electron channeling contrast imaging. Journal of Crystal Growth, 453, pp.65-70.

Li, D., Zhao, X., Wang, L., Conrad, B., Soeriyadi, A.H., Diaz, M., Gerger, A., Lochtefeld, A., Barnett, A. and Perez-Wurfl, I., 2016. Optical absorption of graded buffer layers and short circuit current improvement in SiGe solar cells grown on silicon substrates. Solar Energy Materials and Solar Cells, 157, pp.973-980.

Zhao, X., Li, D., Zhang, T., Conrad, B., Wang, L., Soeriyadi, A.H., Han, J., Diaz, M., Lochtefeld, A., Gerger, A. and Perez-Wurfl, I., 2017. Short circuit current and efficiency improvement of SiGe solar cell in a GaAsP-SiGe dual junction solar cell on a Si substrate. Solar Energy Materials and Solar Cells, 159, pp.86-93.

Li, D., Zhao, X., Wang, L., Conrad, B., Soeriyadi, A., Lochtefeld, A., Gerger, A., Barnett, A. and Perez‐Wurfl, I., 2016. Performance improvement for epitaxially grown SiGe on Si solar cell by optimizing the back surface field. physica status solidi (RRL)-Rapid Research Letters, 10(10), pp.735-738.

Conrad, B., Soeriyadi, A., Li, D., Wang, L., Zhao, X., Lochtefeld, A., Gerger, A., Perez-Wurfl, I. and Barnett, A., 2016, June. Improved GaAsP/SiGe tandem on silicon outdoors and under concentration. In Photovoltaic Specialists Conference (PVSC), 2016 IEEE 43rd (pp. 1942-1946). IEEE.

Gerger, A., Stall, R., Schurman, M., Sharps, P., Sulyma, C., De Zetter, K., Johnson, P., Mitchell, R., Guevara, R., Crist, K. and Cisneros, L., 2016, June. Full wing qualification testing and incremental program update for the solar probe plus array. In Photovoltaic Specialists Conference (PVSC), 2016 IEEE 43rd (pp. 1323-1326). IEEE.

Soeriyadi, A.H., Wang, L., Conrad, B., Zhao, X., Li, D., Lochtefeld, A., Gerger, A., Barnett, A. and Perez-Wurfl, I., 2016, June. Spatially resolved EL and PL coupling of a dual junction solar cell. In Photovoltaic Specialists Conference (PVSC), 2016 IEEE 43rd (pp. 1599-1601). IEEE.

Li, D., Zhao, X., Wang, L., Conrad, B., Soeriyadi, A., Lochtefeld, A., Gerger, A., Perez-Wurfl, I. and Barnett, A., 2016. Performance improvement for epitaxially grown SiGe on Si solar cell using a compositionally graded SiGe base. Applied Physics Letters, 109(24), p.243503.

Conrad, B., Lochtefeld, A., Gerger, A., Barnett, A. and Perez-Wurfl, I., 2017. Optical characterisation of III-V alloys grown on Si by spectroscopic ellipsometry. Solar Energy Materials and Solar Cells, 162, pp.7-12.

Zhao, X., Li, D., Zhang, T., Conrad, B., Wang, L., Soeriyadi, A.H., Han, J., Diaz, M., Lochtefeld, A., Gerger, A. and Perez-Wurfl, I., 2017. Short circuit current and efficiency improvement of SiGe solar cell in a GaAsP-SiGe dual junction solar cell on a Si substrate. Solar Energy Materials and Solar Cells, 159, pp.86-93.