Nuha Ahmed, Lei Zhang, Gowri Sriramagiri, Ujjwal Das, Steven Hegedus. “Electroluminescence analysis for spatial characterization of parasitic optical losses in silicon heterojunction solar cells.” Journal of Applied Physics. 123, 143103 2018. DOI:10.1063/1.5007048
Jeff Bailey, Dmitry Poplavskyy, Geordie Zapalac, Lorelle Mansfield, William Shafarman. “Voltage-Induced Charge Redistribution in Cu(In,Ga)Se2 Devices Studied With High-Speed Capacitance-Voltage Profiling.” Proc. 7th World Conference on Photovoltaic Energy Conversion. , 2018.
Christopher P. Thompson, Isaac Lam, William N. Shafarman. “Characterization and Simulation of Electronic Effects of Front Bandgap Gradients in Selenized/Sulfized Cu(In,Ga)(Se,S)2 Solar Cells.” Proc. 7th World Conference on Photovoltaic Energy Conversion. , 2018.
Nicholas Valdes, JinWoo Lee, and William Shafarman. “Ag Alloying and KF Treatment Effects on Low Bandgap CIGS Solar Cells.” Proc. 7th World Conference on Photovoltaic Energy Conversion. , 2018.
Zeming Sun, Ugo Nsofor, Nuha Ahmed, Ujjwal K. Das, Steven Hegedus, and Mool C. Gupta. “Direct Laser Isolation For Interdigitated Back Contact Heterojunction Solar Cells.” Proc. 7th World Conference on Photovoltaic Energy Conversion. , 2018.
Ujjwal Das, Christopher Thompson, Ugo Nsofor, Zeming Sun, Mool C. Gupta, and Steven Hegedus. “Effect of dielectric layers on laser-fired-contact performance in a-Si/c-Si heterojunction Solar Cells.” Proc. 7th World Conference on Photovoltaic Energy Conversion. , 2018.
Ugo Nsofor, Anishkumar Soman, Ujjwal Das, Steve Hegedus. “Improving the Interface Passivation of Si HJ Solar Cells by Interrupted Deposition of Thin a-Si:H Film.” Proc. 7th World Conference on Photovoltaic Energy Conversion. , 2018.
Duanhui Li, Lan Li, Bradley Jared, Gordon Keeler, Bill Miller, Michael Wood, Christopher Hains, William Sweatt, Scott Paap, Michael Saavedra, Charles Alford, John Mudrick, Ujjwal Das, Steve Hegedus, Anna Tauke-Pedretti, Juejun Hu, Tian Gu. “Wafer Integrated Micro-Scale Concentrating Photovoltaics.” Progress in Photovoltaics. , 2018.
Ugochukwu Nsofor, Lei Zhang, Anishkumar Soman, Christopher Goodwin, H. Liu, Kevin Dobson, Ujjwal Das and Steven Hegedus. “Analysis of silicon wafer surface preparation for heterojunction solar cells using X-ray photoelectron spectroscopy and effective minority carrier lifetime.” Solar Energy Mat. Solar Cell. , 2018.
Sina Soltanmohammad and William N. Shafarman. “Reaction Pathway Analysis of (AgxCu1-x)(In0.75Ga0.25)Se2 with x = 0.75 and 1.0.” Solar Energy Materials & Solar Cells. 182, 142-157 2018. DOI:10.1016/j.solmat.2017.12.023.
Lei Zhang, Nuha Ahmed, Christopher Thompson, Ujjwal Das, and Steve Hegedus. “Study of Passivation in the Gap Region between Contacts of Interdigitated Back Contact Silicon Heterojunction Solar Cells: Simulation and Voltage-modulated Laser-beam-induced-current.” IEEE J Photovoltaics. 8, 404-412 2018. DOI:10.1109/JPHOTOV.2017.2783852
Sina Soltanmohammad, Lei Chen, Brian McCandless, and William N. Shafarman. “Ag–Cu–In–Ga Metal Precursor Thin Films for (Ag,Cu)(In,Ga)Se2 Solar Cells.” IEEE Journal of Photovoltaics. 7, 273-280 2017. DOI:10.1109/JPHOTOV.2016.2615682
Lorelle M. Mansfield, Rebekah L. Garris, Kahl D. Counts, James R. Sites, Christopher P. Thompson, William N. Shafarman, and Kannan Ramanathan. “Comparison of CIGS Solar Cells Made With Different Structures and Fabrication Techniques.” IEEE Journal of Photovoltaics. 7, 286-293 2017. DOI:10.1109/JPHOTOV.2016.2616188
Bradley M. West, Michael Stuckelberger , Harvey Guthrey, Lei Chen, Barry Lai, Jörg Maser, Volker Rose, William Shafarman, Mowafak Al-Jassim, Mariana I. Bertoni. “Grain engineering: How nanoscale inhomogeneities can control charge collection in solar cells.” Nano Energy. 32, 488–493 2017. DOI:10.1016/j.nanoen.2016.12.011
Lei Chen, Sina Soltanmohammad, JinWoo Lee, Brian E. McCandless, William N. Shafarman. “Secondary Phase Formation in (Ag,Cu)(In,Ga)Se2 Thin Films Grown by Three-stage Co evaporation.” Solar Energy Materials & Solar Cells. 166, 18-26 2017. DOI:10.1016/j.solmat.2017.03.001
Sina Soltanmohammad, Brian McCandless, William N. Shafarman. “A quaternary Laves-type phase in Ag-Cu-In-Ga thin films.” Journal of Alloys and Compounds. 710, 819-824 2017. DOI:10.1016/j.jallcom.2017.03.228
Douglas M. Bishop, Brian McCandless, Talia Gershon, Michael A. Lloyd, ,Richard Haight, Robert Birkmire. “Modification of defects and potential fluctuations in slow-cooled and quenched Cu2ZnSnSe4 single crystals.” J. Applied Physics. 121, 065704 2017.
U Das and S Hegedus. “Processing Approaches and Challenges of Interdigitated Back Contact Si Solar Cells.” Proc. 44th IEEE Photovoltaic Specialist Conference. , 2017.
Sina Soltanmohammad and William N. Shafarman. “RTP-assisted Ex-situ Analysis of (Ag,Cu)(In,Ga)Se2 Formation using Selenization.” Proc.44th IEEE Photovoltaic Specialists Conference. , 2017.
Anishkumar Soman, Ugochukwu Nsofor, Lei Zhang, Ujjwal Das and Steven Hegedus. “Hydrogen Plasma Post-Deposition Treatment for Passivation of a-Si/c-Si Interface for Heterojunction Solar Cell by Correlating Optical Emission Spectroscopy and Minority Carrier Lifetime.” Proc. 44th IEEE Photovoltaic Specialists Conference. , 2017.
Anishkumar Soman, Jianping Shi, Ugochukwu Nsofor, Steven Hegedus, Yanfeng Zhang, Robert A. Burke and Tingyi Gu. “Raman spectroscopy study of Hydrogen Plasma Treatment effect on a single layer Graphene/MoS2 hybrid structure.” Frontiers in Optics Conference. , 2017.
Nuha Ahmed, Lei Zhang, Ujjwal Das, and Steven Hegedus. “Electroluminescence Analysis for Separation of Series Resistance From Recombination Effects in Silicon Solar Cells with Interdigitated Back Contact Design.” Proc. 44th IEEE Photovoltaic Specialists Conference. , 2017.
Gowri M. Sriramagiri, Nuha Ahmed, Wesley Luc, Kevin D. Dobson, Steven S. Hegedus, Feng Jiao. “Towards Practical Solar-Driven CO2 Flow-Cell Electrolyzer: Design and Optimization.” American Chemical Soc. Sustainable Chemistry and Engineering. 5, 10959–10966 2017. DOI:10.1021/acssuschemeng.7b02853
Charles W. Warren, Ellis T. Roe, D. Westley Miller, William N. Shafarman, Mark C. Lonergan. “An improved method for determining carrier densities via drive level capacitance profiling.” Applied Physics Letters. 110, 203901 2017.
Sina Soltanmohammad, Lei Chen, Brian McCandless, William N. Shafarman. “Phase Stability in Ag-Cu-In-Ga Metal Precursors for (Ag,Cu)(In,Ga)Se2 Thin Films.” Solar Energy Materials & Solar Cells. 172, 347–352 2017.
Marika Edoff, Tobias Jarmar, Nina Shariati Nilsson, Erik Wallin, Daniel Högström, Olof Stolt, Olle Lundberg, William Shafarman and Lars Stolt. “High VOC in (Cu,Ag)(In,Ga)Se2 solar cells.” IEEE Journal of Photovoltaics. 7, 1789-1794 2017.
Hsiang-Yu Liu, Ujjwal K. Das, Robert W. Birkmire. “Surface Defect Passivation and Reaction of c-Si in H2S.” Langmuir. 33, 14580–14585 2017. 10.1021/acs.langmuir.7b03520
Robert J. Lovelett, Xueqi Pang, Tyler M. Roberts, William N. Shafarman, Robert W. Birkmire, Babatunde A. Ogunnaike. “A stochastic model of solid state thin film deposition: application to chalcopyrite growth.” AIP Advances. 6, 045015 2016. DOI:10.1063/1.4948404
Peipei Xin, Jes K. Larsen, Fei Deng, William N. Shafarman. “Development of Cu(In,Ga)Se2 superstrate devices with alternative buffer layers.” Solar Energy Materials & Solar Cells. 157, 85-92 2016. DOI:10.1016/j.solmat.2016.05.018
Bradley West, Michael Stuckelberger, Harvey Guthrey, Lei Chen, Barry Lai, Jorg Maser, Volker Rose, James J. Dynes, William Shafarman, Mowafak Al-Jassim, Mariana Bertoni. “Synchrotron x-ray characterization of alkali elements at grain boundaries in Cu(In,Ga)Se2 solar cells.” Proc. 43rd IEEE Photovoltaic Specialists Conference. , 31-34 2016. DOI:10.1109/PVSC.2016.7749403
Jaseok Koo, Sunmo Kwon, Yong-Suk Roh, Seok-Jin Lee, Ki-Young Jung, William N. Shafarman, Ji-Hyeon Park, Do Hoon Kim, Jae-Min Myoung, Woo Kyoung Kim. “Effect of Reaction Temperature and Time during Two-Step Selenization and Sulfurization of Se-Coated CuGa/In Precursors.” Electronic Materials Letters. 12, 484-493 2016. DOI:10.1007/s13391-016-4011-2
Robert J. Lovelett, Gregory M. Hanket, William N. Shafarman, Robert W. Birkmire, Babatunde A. Ogunnaike. “Design and experimental implementation of an effective control system for thin film Cu(InGa)Se2 production via rapid thermal processing.” Journal of Process Control. 46, 24-33 2016. DOI:10.1016/j.jprocont.2016.07.005
Kihwan Kim, William N. Shafarman. “Alternative device structures for CIGS-based solar cells with semi-transparent absorbers.” NanoEnergy. 30, 488-493 2016. DOI:10.1016/j.nanoen.2016.10.038
• “Reversibility of (Ag,Cu)(In,Ga)Se2 electrical properties with the addition and removal of Na: Role of grain boundaries,” Robert Forest, Erten Eser, Brian McCandless, Jingguang Chen, and Robert Birkmire, Manuscript #JR15-0621
• “Fabrication and Electronic Properties of CZTSe Single Crystals,” Douglas M. Bishop, Brian E. McCandless, Richard Haight, David B. Mitzi, Robert W. Birkmire IEEE Journal of Photovoltaics 01/2015; 5(1):390-394. DOI:10.1109/JPHOTOV.2014.2363552
• “Structural, optical, and surface properties of WO3 thin films for solar cells,” H. Simchi, B.E. McCandless, T.Meng, W.N. Shafarman, Journal of Alloys and Compounds 617, 609-615 (2014).
• “Understanding the role of oxygen in the segregation of sodium surface of molybdenum coated soda-lime glass,” Robert V. Forest, Erten Eser, Brian E. McCandless, Robert W. Birkmire, Jingguang G. Chen, Article first published on line: 11 MAR 2014; DOI: 10.1002/aic. 14425. AICHE Journal, June (2014) 60 (6) 2365-2372.
• “Microstructure and phase evolution in single phase CuInSe2 particles synthesized using elemental precursors,” Emre Yassitepe, William N. Shafarman, Ismat Shah, Journal of Solid State Chemistry 213- Journal of Solid State Chemistry, 23, 198-203 (2014).
• “The role of back contact patterning on stability and performance of Si IBC heterojunction solar cells” U. Das, H-Y Liu, J. He, S. Hegedus, Proc. 40th IEEE PVSC, Proc. 40th IEEE Photovoltaic Specialists Conference; Denver, CO; June 8-13, 2014.
• “Laser fired contacts for n-type c-Si solar cells,” J. He, S. Hegedus, U. Das, Z. Shan, M. Bennett, L. Zhang, R. Birkmire Progress in Photovoltaics, published online: 17 June 2014 DOI: 10.1002/pip.2520.
• “H2S reaction of Se-capped metallic precursors to form Cu(In,Ga)(S,Se)2 absorber layers,” Dominik M. Berg, Frank Cheng, and William N. Shafarman Proc. 40th IEEE PVSC, Denver CO, June 9-13, 2014.
• “Effect of sputtering sequence on the properties of Ag-Cu-In-Ga metal precursors and reacted (Ag,Cu)(In,Ga)Se2 films,” Sina Soltanmohammad, Dominik M. Berg, Lei Chen, Kihwan Kim, Hamed Simchi, William N.Shafarman; Proc. 40th IEEE PVSC, Denver CO, June 9-13, 2014.
• “Controlled bandgap CuIn1− xGax(S0.1Se0.9)2 (0.10 ≤ x ≤ 0.72) solar cells from electrodeposited precursors,” João C. Malaquias, Dominik M. Berg, Jan Sendler, Marc Steichen, Nathalie Valle, Phillip J. Dale, J.C. Malaquias, et al., Thin Solid Films In Press (2014). http://dx.doi.org/10.1016/j.tsf.2014.10.068
• “CdTe Solar Cells with a PCBM Back Contact,” Curtis Walkons, Brett Guralnick, Brian McCandless, and Robert Birkmire, Proc. 40th IEEE PVSC (2014).
• “Improved Performance of Ultrathin Cu(InGa)Se2 Solar Cells With a Backwall Superstrate Configuration,” Hamed Simchi, Jes K. Larsen, Kihwan Kim, and William N. Shafarman; IEEE Journal of Photovoltaics, Vol. 4, No. 6, (2014).
• “Transparent Back Contacts for Superstrate (Ag,Cu)(In,Ga)Se2 Thin Film Solar Cells,” H. Simchi, J. K. Larsen, and W. N. Shafarman, IEEE Journal of Photovoltaics, Proc. 40th IEEE PVSC, Denver CO, June 9-13, 2014.
• “The Comparison of (Ag,Cu)(In,Ga)Se2 andCu(In,Ga)Se2 Thin Films Deposited by Three-Stage Coevaporation,” Lei Chen, JinWoo Lee, and William N. Shafarman, to be published in IEEE Journal Of Photovoltaics.
• “Characterization of Group I-rich Growth During (Ag,Cu)(In,Ga)Se2 Three-stage Co-evaporation,” Lei Chen, JinWoo Lee, Brian E. McCandless, Sina S. Soltanmohammad, William N. Shafarman, Proc. 40th IEEE PVSC, Denver CO, June 9-13, 2014.
• “Laser Fired Contact for n-Type Crystalline Si Solar Cells,” He, Jianbo; Hegedus, Steven, Das, Ujjwal K., Shu, Zhan, Bennett, Murray, Zhang, Lei, Birkmire, Robert, to be published in Progress in Photovoltaics: Research and Applications.
• “The role of back contact patterning on stability and performance of Si BC heterojunction solar cells,” Ujjwal K. Das, Hsiang-Yu Liu, Jianbo He, and Steven Hegedus, Proc. 40th IEEE PVCS; Denver, CO; June 8-13, 2014.
• “Demonstration of High-Performance, Sub-Micron Chalcogenide Glass Photonic Devices by Thermal Nanoimprint,” Y. Zou, L. Moreel, J. Zhou, D. Zhang, H. Lin, Lan Li, Q. Du, J. Hu, S. Danto, K. Richardson, J. D. Musgraves, K. D. Dobson and R. Birkmire, Proc. SPIE 8988, 898806 (2014). DOI: 10.1117/12.2040454.
• “High-Performance, High-Index-Contrast Chalcogenide Glass Photonics on Silicon and Unconventional Non-planar Substrates,” Y. Zou, D. Zhang, H. Lin, L. Li, L. Moreel, J. Zhou, Q. Du, O. Ogbuu, S. Danto, J. D. Musgraves, K. Richardson, K. D. Dobson, R. Birkmire and J. Hu, Adv. Opt. Mater. 2 478-486 (2014). DOI: 10.1002/adom.201300489
• “Solution Processing and Resist-Free Nanoimprint Fabrication of Thin Film Chalcogenide Glass Devices: Inorganic-Organic Hybrid Photonic Integration,” Y. Zou, L. Moreel, H. Lin, J. Zhou, L. Li, S. Danto, J. D. Musgraves, E. Koontz, K. Richardson, K. D. Dobson, R. Birkmire and J. Hu, Adv. Opt. Mater. 2 759-764 (2014). DOI: 10.1002/adom.201300489
• “Structural and optical properties of (Ag,Cu)(In,Ga)Se2 polycrystalline thin film alloys” J. H. Boyle, B. E. McCandless, W. N. Shafarman, and R. W. Birkmire Journal of Applied Physics 115 , 223504 (2014); doi: 10.1063/1.4880243
• “Diffusion Mechanism of Na in Molybdenum Thin Films for Improving Cu(In,Ga)Se2 Solar Cell Efficiency” Robert V. Forest, Brian E. McCandless, Robert W. Birkmire, Jingguang G. Chen 2014 AIChE Annual meeting in Atlanta. URL http://www3.aiche.org/proceedings/Abstract.aspx?PaperID=377524
• “Electrophoretic Deposition of Aluminum Nitride from Its Suspension in Acetylacetone Using Iodine as an Additive,” Bizuneh Workie, Brian E. McCandless, and Zewdu Gebeyehu, Hindawi Publishing Corp, Journal of Chemistry, Volume 2013, Article ID 489734, (2013). http://dx.doi.org/10.1155/2013/489734
• “Sensitivity of surface passivation and interface quality in IBC-SHJ solar cells to patterning process,” Ujjwal Das, Jianbo He, Zhan Shu, Lulu Zhang, Chris Thompson, Robert Birkmire and Steven Hegedus, Proc., 39th IEEE PVSC, Tampa, FL (2013).
• “Laser fired contact for n-type crystalline Si solar cell,” J. He, S. Hegedus, U. Das, Z. Shu, M. Bennett, and R. Birkmire, Proc. 39th IEEE PVSC, Tampa, FL (2013). “In-situ resistance measurement during the growth of Cu(In,Ga)Se2 films by multi-source evaporation,” JinWoo Lee, Lei Chen, Uwa Obahiagbon, Chris Thompson, William N. Shafarman and Robert W. Birkmire, Proc. 39th IEEE PVSC, Tampa FL, June 17-21, 2013.
• “Understanding the Effect of Na in Improving the Performance of Cu(InGa)Se2-Based Photovoltaics,” Robert V. Forest, Kunhee Han, Erten Eser, Jingguang G. Chen, Robert W. Birkmire, Proc. 39th IEEE Journal of Photovoltaics, 4, 948, (2014).
• “Light Trapping in Thin Film Cu(InGa)Se2 Solar Cells,” James G. Mutitu, Uwadiae Obahiagbon, Shouyuan Shi, William Shafarman and Dennis W. Prather, Proc. IEEE Journal of Photovoltaics, 4, 948, (2014).
• “Structure and Interface Chemistry of MoO3 Back Contacts in Cu(In,Ga)Se2 Thin Film Solar Cells,” Hamed Simchi, Brian E. McCandless, T. Meng, and William N. Shafarman, Journal of Applied Physics 115, 033514 (2014). http://dx.doi.org/10.1063/1.4862404
• “Backwall Superstrate Configuration for Ultrathin Cu(In,Ga)Se2 Solar Cells,” J. K. Larsen, H. Simchi, P. Xin, K. Kim, and W. N. Shafarman, Applied Physics Letters 104, 033901 (2014). http://dx.doi.org/10.1063/1.4862651
• “Experimental and simulated analysis of front versus all-back- contact silicon heterojunction solar cells: effect of interface and doped a-Si:H layer defects,” Zhan Shu, Ujjwal Das, John Allen, Robert Birkmire and Steven Hegedus, Progress In Photovoltaics: Research And Applications (2013) Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/pip.2400.
• “Effect of RF or VHF Plasma on Nanocrystalline Silicon Thin Film Structure: Insight from OES and Langmuir Probe Measurements,” Lala Zhu, Ujjwal K. Das, Steven S. Hegedus, Robert W. Birkmire, Mat. Res. Soc. Symp. Proc. 1538, 3 (2013); DOI http://dx.doi.org/10.1557/opl.2013.924
• “Optimizing emitter-buffer layer stack thickness for p-type silicon heterojunction solar cells,” Zeynep Deniz Eygi, Ujjwal Das, Steven Hegedus, and Robert Birkmire, J. Renewable Sustainable Energy 5, 013117 (2013); DOI: 10.1063/1.4792510 View online: http://dx.doi.org/10.1063/1.4792510
• “Temperature Sensing and Control in a Rapid Thermal Processing Reactor to Produce CuInGaSe2 Absorber Layers” Robert J. Lovelett, Robert W. Birkmire, Babatunde A. Ogunnaike 2014 AIChE Annual meeting in Atlanta URL http://www3.aiche.org/proceedings/Abstract.aspx?PaperID=331025
• “Effects of Growth Conditions on Secondary Phases in CZTSe Thin Films Deposited by Co-evaporation” Douglas M. Bishop, Brian E. McCandless, Thomas C. Mangan, Kevin Dobson, Robert Birkmire MRS Online Proceeding Library 01/2013; 1538:75-82. DOI:10.1557/opl.2013.1005
• “Effect of surface carbon on the hydrogen evolution reactivity of tungsten carbide (WC) and Pt-modified WC electrocatalysts,” Yannick C. Kimmel, Daniel V. Esposito, Robert W. Birkmire, Jingguang G. Chen, International Journal of Hydrogen Energy, in-press (2012).
• “Electron drift-mobility measurements in polycrystalline CuIn1-xGaxSe2 solar cells,” S. A. Dinca, E. A. Schiff, W. N. Shafarman, B. Egaas, R. Noufi, and D. L. Young, Applied Phys Letters, 100, 103901 (2012).
• “Three-step H2Se/Ar/H2S reaction of Cu-In-Ga precursors for controlled composition and adhesion of Cu(In,Ga)(Se,S)2 thin films,” Kihwan Kim, Gregory M. Hanket, Trang Huynh, William N.Shafarman, J. Applied Phys, 111, 083710 (2012).
• “Photoelectrochemical reforming of glucose for hydrogen production using a WO3-based tandem cell device,” Daniel V. Esposito, Robert V. Forest, Yuancheng Chang, Nicolas Gaillard, Brian E. McCandless, Shuyu Hou, Kelvin H. Lee, Robert W. Birkmire, Jingguang G. Chen, Energy Environ. Sci., 5, 9091-9099 (2012).
• “Impact of back surface patterning process on FF in IBC-SHJ solar cell,” Lulu Zhang, Brent Shu, Robert Birkmire, Steve Hegedus, Ujjwal Das, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “Design of anti-reflection coating for surface textured interdigitated back contact silicon hetero-junction solar cell,” Brent Shu, Ujjwal Das, Lei Chen, Lulu Zhang, Steven Hegedus, Robert Birkmire, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “Characterization and modeling of low temperature surface passivation for interdigitated back contact silicon hetero-junction solar cell,” Brent Shu, Ujjwal Das, Steven Hegedus, Robert Birkmire, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “Laser textured heterojunction solar cells on 45 um thick Si wafers: effect of optical configuration and light trapping” Steven Hegedus, Ujjwal Das1, Chris Vineis2, Moran Levy-Finklshtein , Jason Sickler, Jim Carey, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “The effects of device geometry and TCO/buffer layers on damp heat accelerated lifetime testing of Cu(In,Ga)Se2 solar cells,” Chris Thompson, Steve Hegedus, Peter Carcia, R. Scott McLean, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “Effect of annealing atmosphere and temperature on the properties of Cd2SnO4 thin films,” Tiejun Meng, Brian E. McCandless, Wayne A. Buchanan, Robert W. Birkmire, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “Control of Ga profiles in (AgCu)(InGa)Se2 absorber layers deposited on polyimide substrates,” Gregory M. Hanket, Christopher P. Thompson, Erten Eser, William N. Shafarman, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “Three-step H2Se/Ar/H2S reaction of metal precursors for large area Cu(In,Ga)(Se,S)2 with uniform Ga distribution,” Kihwan Kim, Evan L. Kimberly, Andrew Damiani, Gregory M. Hanket, William N. Shafarman, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “High efficiency ultra-thin Cu(In,Ga)(Se,S)2 solar cells by three-step H2Se/Ar/H2S reaction of Cu-In-Ga metal precursor,” Kihwan Kim, Hyeonwook Park, Woo Kyoung Kim, Gregory M. Hanket, William N. Shafarman, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “Characterization of (AgCu)(InGa)Se2 absorber layer fabricated by selenization process from metal precursor,” Yuki Tauchi, Kihwan Kim, Hyeonwook Park, William Shafarman, Proc. 38th IEEE PVSC, Austin, TX, June 3-6, 2012.
• “Laser textured heterojunction solar cells on 45 um thick Si wafers: effect of optical configuration and light trapping,” Steven Hegedus, Ujjwal Das, Chris Vineis, Moran Levy-Finklshtein, Jason Sickler, Jim Carey, Proc. 38th IEEE PVSC, Austin TX, June 2012
• “Analysis of voltage and temperature dependent photocurrent collection in p3ht/pcbm solar cells,” Bakhtyar Ali, Roy Murray, Steven S. Hegedus, and S. Ismat Shah, J. Appl. Phys. 112, 114514 (2012).
• “Review of photovoltaic module energy yield (kWh/kW): comparison of crystalline Si and thin film technologies,” Steven Hegedus, Wiley WIRE Energy Environ 2012. doi: 10.1002/wene.61.
• “Review of photovoltaic module energy yield (kWh/kW): comparison of crystalline Si and thin film technologies,” Steven Hegedus, WIREs Energy Environ. doi: 10.1002/wene.61 (2012)
• “Metal-Modified Tungsten and Molybdenum Carbide Electrocatalysts for Energy Conversion” Yannick C. Kimmel, Daniel V. Esposito, Robert W. Birkmire, Jingguang G. Chen 12 AIChE Annual Meeting; 10/2012
• “An Investigation of the Surface Properties of (Ag,Cu)(In,Ga)Se2 Thin Films” H. Simchi, B.E. McCandless, K. Kim, J.H. Boyle, R.W. Birkmire, W.N. Shafarman IEEE Journal of Photovoltaics 10/2012; 2(4):519-523.
• “Cadmium tin oxide thin films deposited by RF magnetron sputtering for photovoltaic applications” Tiejun Meng, Brian McCandless, Wayne Buchanan, Evan Kimberly, Robert Birkmire Journal of Alloys and Compounds 04/2013; 556:39–44. DOI:10.1016/j.jallcom.2012.12.146
• “Atomic layer deposition of pt on tungsten monocarbide (WC) for the oxygen reduction reaction,” Irene J. Hsu, Danielle A. Hansgen, Brian E. McCandless, Brian G. Willis, Jingguang Chen, J. Phys. Chem. 115, 3709-3715 (2011).
• “Ga homogenization by simultaneous H2Se/H2S reaction of Cu-Ga-In precursor,” Woo Kyoung Kim, Gregory M. Hanket, William N. Shafarman, J. Sol. Mat. 95, 235-238 (2011).
• “Metastable properties of Cu(In1-xGax)Se2 with and without sodium,” Peter T. Erslev, William N. Shafarman, J. David Cohen, Applied Physics Letters 98, 062105 (2011).
• “Hydrogen production from photo-driven electrolysis of biomass-derived oxygenates: A case study on methanol using Pt-modified WO3 thin film electrodes,” Daniel V. Esposito, Jingguang G. Chen, Robert W. Birkmire, Yuancheng Chang, Nicolas Gaillard, International Journal of Hydrogen Energy 36, 9632-9644 (2011).
• “Structural characterization of the (AgCu)(InGa)Se2 thin film alloy system for solar cells,” J.H. Boyle, B.E. McCandless, G.M. Hanket, W.N. Shafarman, Thin Solid Films (2011).
• “Improved FF in p-Si heterojunction solar cells due to optimized ITO/emitter contact,” Zeynep Eygi, Ujjwal Das, Steven Hegedus, Robert Birkmire, Proc. 37th IEEE PVSC, Seattle WA, June 20-24, 2011.
• “Surface Characterization of (AgCu)(InGa)Se2 Thin Films for Solar Cells,” Hamed Simchi, Brian McCandless, William Shafarman, Kihwan Kim, Jonathan Boyle, and Robert Birkmire, Proc. 37th IEEE PVSC, Seattle WA, June 20-24, 2011.
• “Cu-In-Ga Metal Precursors Sputter Deposited from a Single Ternary Target for Cu(lnGa)(SeS)2 Film Formation,” Trang Huynh, Wayne Buchanan, Kihwan Kim, Brian McCandless, William Shafarman, Robert Birkmire, Proc. 37th IEEE PVSC, Seattle WA, June 20-24, 2011.
• “Interdigitated back contact silicon hetero-junction solar cells: the effect of doped layer defect levels on fill factor using two-dimensional simulations,” John Allen, Brent Shu, Ujjwal Das, Steven Hegedus, Proc. 37th IEEE PVSC, Seattle WA, June 20-24, 2011.
• “Atomic Layer Deposition of Pt on Tungsten Monocarbide (WC) for the Oxygen Reduction Reaction,” Irene J. Hsu, Danielle A. Hansgen, Brian E. McCandless, Brian G. Willis, and Jingguang G. Chen, The Journal of Physical Chemistry, 115, 3709-3715, C (2011).
• “Properties of amorphous silicon passivation layers for all back contact c-Si heterojunction solar cells” Lulu Zhang, Ujjwal Das, Jesse Appel, Steve Hegedus, Robert Birkmire. Mater. Res. Soc. Symp. Proc. Vol. 1321 © 2011 Materials Research Society DOI: 10.1557/opl.2011.942
• “Cu(In,Ga)Se2 Film Formation From Selenization of Mixed Metal/Metal-selenide Precursors,” Rui Kamada, William N. Shafarman and Robert W. Birkmire, Solar Energy Materials & Solar Cells 94, 451 (2010).
• “A Comparative Study of Photoconductivity and Carrier Transport in a-Si:H p-i-n Solar Cells with Different Back Contacts,” R. Kaplan, B. Kaplan, S.S. Hegedus, Solid-State Electronics 54, 22 (2010).
• “Device Characterization of (AgCu)(InGa)Se2 Solar Cells,” William Shafarman, Christopher Thompson, Jonathan Boyle, Gregory Hanket, Peter Erslev and J. David Cohen, Proc. 35th IEEE PVSC, Waikiki, Hawaii, June 21-25, 2010.
• “Commercial-Scale Sources for the Evaporation of Elemental Cu, Ga, and In: Modeling, Design and Validation,” Gregory M. Hanket, Robert W. Birkmire, Shannon Fields, and Erten Eser, Proc. 35th IEEE PVSC, Waikiki, Hawaii, June 21-25, 2010.
• “Wide-bandgap (AgCu)(InGa)Se2 Absorber Layers Deposited by Three-stage Co-evaporation, Gregory Hanket, Jonathan H. Boyle, William N. Shafarman, and Glenn Teeter, Proc. 35th IEEE PVSC, Waikiki, Hawaii, June 21-25, 2010.
• “Alternative Approaches for Low Temperature Front Surface Passivation of Interdigitated Back Contact Silicon Heterojunction Solar Cell,” Brent Shu, Ujjwal Das, Jesse Appel, Brian McCandless, Steven Hegedus and Robert Birkmire, Proc. 35th IEEE PVSC, Waikiki, Hawaii, June 21-25, 2010.
• “Encapsulation of Cu(InGa)Se2 Solar Cells with ALD Al2O3 Flexible Thin-film Moisture Barrier; Stability Under 1000 Hour Damp Heat and UV Exposure,” Steven S. Hegedus, P.F. Carcia, R.S. McLean, Bradley Culver, Proc. 35th IEEE PVSC, Waikiki, Hawaii, June 21-25, 2010.
• “Quantitative Analysis and Extraction of Cell Parameters from Interconnected Thin-Film Solar Modules Through LBIC-voltage Sweeps,” Jonathan M. Frey, Steven S. Hegedus, and Christopher P. Thompson, Proc. 35th IEEE PVSC, Waikiki, Hawaii, June 21-25, 2010.
• “Investigation of Hetero-interface and Junction Properties in Silicon Heterojunction Solar Cells,” Ujjwal Das Steven Hegedus, Lulu Zhang, Jesse Appel, Jim Rand, and Robert Birkmire, Proc. 35th IEEE PVSC, Waikiki, Hawaii, June 21-25, 2010.
• “Cu(InGa)Se2 Photovoltaics on Insulated Stainless Steel Web Substrate,” Erten Eser, Shannon Fields, Woo K. Kim, Elizabeth McQuiston, Kihwan Kim, and William N. Shafarman, Proc. 35th IEEE PVSC, Waikiki, Hawaii, June 21-25, 2010.
• “Effect of Junction Interface Modification of Silicon Heterojunction Solar Cells,” Jesse Appel, Lulu Zhang, Ujjwal Das, Steven Hegedus, Swapna Mudigonda, Robert Birkmire, Jim Rand, Proc. 35th IEEE PVSC, Waikiki, Hawaii, June 21-25, 2010.
• “Optimization of Interdigitated Back Contact Silicon Heterojunction Solar Cells: Tailoring Hetero-interface Band Structures While Maintaining Surface Passivation,” Meijun Lu, Ujjwal Das, Stuart Bowden, Steven Hegedus and Robert Birkmire, Prog. Photovolt. Res. Appl. DOI: 10.1002/pip. 1032 (2010).
• “Commercial-Scale Deposition of Cu(InGa)Se2 Thin Films by Thermal Evaporation,” Gregory M. Hanket, Future Photovoltaics, Sept (2010).
• “Aluminum-induced crystallization of amorphous silicon films deposited by hot wire chemical vapor deposition on glass substrates,” Ozgenc Ebil, Roger Aparicio, Robert Birkmire, Thin Solid Films 510, 178 (2010).
• “Encapsulation of Cu(InGa)Se2 Solar Cell with Al2O3 Thin-film Moisture Barrier rown by Atomic Layer Deposition,” P.F. Carcia, R.S. McLean, Steven Hegedus, Solar Energy Materials & Solar Cells 94, 2375-2378 (2010).
• “Thin-Film Solar Cells and Modules,” Robert W. Birkmire, Solar Cells and Their Applications, Second Edition book (Wiley Series in Microwave and Optical Engineering), Chapter 6, 137-157 (2010).
• “CdTe thin film technology: Leading thin film PV into the future,” Robert W. Birkmire, Brian E. McCandless, Current Opinion in Solid State and Materials Science 14, 139-142 (2010).
• “Low-cost hydrogen-evolution catalysts based on monolayer platinum on tungsten monocarbide substrates,” Daniel Esposito, Sean T. Hunt, Alan L. Stottlemyer, Kevin D. Dobson, Brian E. McCandless, Robert W. Birkmire, Jingguang G. Chen, Angew. Chem. Int. Ed. 49, 9859-9862 (2010).
• “Electrochemical stability of tungsten and tungsten monocarbide (WC) Over Wide pH and Potential Ranges,” Mark C. Weidman, Daniel Esposito, Irene J. Hsu, Jingguang Chen, J. Electrochem. Soc. 157 (12).
• “The Influence of Na on Metastable Defect Kinetics in CIGS Materials,” Peter T. Erslev, Jin Woo Lee, William N. Shafarman, J. David Cohen, J. Thin Film Solids 517, 2277-2381 (2009).
• “Optimization of Interdigitation Parameters for Back Contact Si Heterojunction Solar Cells,”O. Jani, U. Das, S. Herasimenka, M. Lu, D. Xu, S. Bowden, S. Hegedus, R. Birkmire, PVSEC18 (2009).
• “Designing Rear Surface for Carrier Transport in Back Contact Si Heterojunction Solar Cells,” U. Das, M. Lu, D. Xu, O. Jani, S. Bowden, S. Hegedus, R. Birkmire, PVSEC18 (2009).
• “In-situ Post-deposition Thermal Annealing of Co-evaporated Cu(InGa)Se2 Thin Films Deposited at Low Temperatures,” James D. Wilson, Brian E. McCandless, Robert W. Birkmire, William N. Shafarman, Proc. 34th IEEE PVSC, Philadelphia, PA, June 8-12, 2009.
• “Characterization and Device Performance of (AgCu)(InGa)Se2 Absorber Layers,” Gregory M. Hanket, Jonathan H. Boyle, and William N. Shafarman, Proc. 34th IEEE PVSC, Philadelphia, PA, June 8-12, 2009.
• “Processing of Cu(In,Ga)Se2 Solar Cells from Electrodeposited Precursors,” Kevin D. Dobson and Robert W. Birkmire, Proc. 34th IEEE PVSC, Philadelphia, PA, June 8-12, 2009.
• “Ga Distribution and Adhesion Issues in Selenization of Metallic Cu-Ga-In Precurcors,” Woo Kyoung Kim, Gregory M. Hanket and William N. Shafarman, Proc. 34th IEEE PVSC, Philadelphia, PA, June 8-12, 2009.
• “Optimization of Interdigitated Back Contact Silicon Heterojunction Solar Cells by Two-dimensional Numerical Simulation,” Meijun Lu, Ujjwal Das, Stuart Bowden, Steven Hegedus and Robert Birkmire, Proc. 34th IEEE PVSC, Philadelphia, PA, June 8-12, 2009.
• “Low Temperature Front Surface Passivation of Interdigitated Back Contact Silicon Heterojunction Solar Cell,” Brent Shu, Ujjwal Das, Omkar Jani, Steven Hegedus, and Robert Birkmire, Proc. 34th IEEE PVSC, Philadelphia, PA, June 8-12, 2009.
• “Optical and Quantum Efficiency Analysis of (Ag,Cu)(In,Ga)Se2 Absorber Layers,” Jonathan Boyle, Gregory Hanket and William Shafarman, Proc. 34th IEEE PVSC, Philadelphia, PA, June 8-12, 2009.
• “Roll-to-Roll Deposition of a Semiconductor Film on a Flexible Substrate for Photovoltaics: Conception to Reality,” Gregory M. Hanket, Robert W. Birkmire, Scott C. Jackson and Richard E. Rocheleau, Ind. Eng. Chem. Res. 48, 5923-5933 (2009).
• “Scaleup of Cu(InGa)Se2 Thin Film Coevaporative Physical Vapor Deposition Process, 1. Evaporation Source Model Development,” Kapil Mukati, Babatunde A. Ogunnaike, Erten Eser, Shannon Fields, and Robert W. Birkmire, Ind. Eng. Chem. Res. 48, 5975-5991 (2009).
• “Understanding Defect-related Issues Limiting Efficiency of CIGS Solar Cells,” Matgorzata Igalson, Pawel Zabierowski, Daniel Przado, Aleksander Urganiak, Marika Edoff, William N. Shafarman, Solar Energy Materials & Solar Cells 93, 1290-1295 (2009).
• “Pin Double-heterojunction Thin-film Solar Cell p-layer Assessment,” J.A. Spies, R. Schafer, J.F. Wager, P. Hersh, H.A.S. Platt, D.A. Keszler, G. Schneider, R. Kykyneshi, J. Tate, X. Lu, A.D. Compaan, W.N. Shafarman, Solar Energy Materials & Solar Cells 93, 1296-1308 (2009).
• “Characterizing the Effects of Silver Alloying in Chalcopyrite CIGS Solar Cells with Junction Capacitance Methods,” Peter T. Erslev, Gregory M. Hanket, William N. Shafarman, and J. David Cohen, Mater. Res. Soc. Symp. 1165, 1165-M01-07 (2009).
• “A New Photoelectrochemical Test Cell and Its Use for a Combined Two-electrode and Three-electrode Approach to Cell Testing,” Daniel V. Esposito, Ouloide Y. Goue, Kevin D. Dobson, Brian E. McCandless, Jingguang G. Chen, and Robert W. Birkmire, Review of Scientific Instruments 80, 125107 (2009).
• “A Comparative Study of Tungsten Monocarbide and Platinum as Counterelectrodes in Polysulfide-Based Photoelectrochemical Solar Cells,” D.V. Esposito, K.D. Dobson, B.E. McCandless, R.W. Birkmire and J.G. Chen, J. Electrochem. Soc. 156, B962-B969 (2009).
• “Hole drift mobility measurements in polycrystalline CuIn1-xGaxSe2,” S. A. Dinca, E. A Schiff, B. Egaas, R. Noufi, D. L. Young, W. N. Shafarman, Physical Review B 80, 235201 (2009).
• “Characterization of ALD copper thin film on palladium seed,” layers, Irene J. Hsu, Brian McCandless, Conan Weiland, and Brian G. Willis, Journal of Vacuum Science and Technology A, Citation: J Vac. Sci. Technol. A 27, 660 (2009).