Now showing items 42-59 of 59

    • Optimization of Self-Doping Ag Paste Firing to Achieve High Fill Factors on Screen- Printed Silicon Solar Cells with a 100 Ω/sq. Emitter 

      Hilali, Mohamed M.; Jeong, Ji-Weon; Rohatgi, Ajeet; Meier, D. L.; Carroll, A. F. (Georgia Institute of Technology, 2002-05)
      Self-aligned selective-emitter cells have been fabricated using a self-doping paste by co-firing the front and back contacts. Good ohmic contacts with ~0.774 fill factor were obtained on 100 Ω/sq. emitters after alloying ...
    • PECVD SiN(x) Induced Hydrogen Passivation in String Ribbon Silicon 

      Yelundur, Vijay; Rohatgi, Ajeet; Jeong, Ji-Weon; Gabor, A. M.; Hanoka, J. I.; Wallace, R. L. (Georgia Institute of Technology, 2000-09)
      To improve the bulk minority carrier lifetime in String Ribbon silicon, SiN(x) induced defect passivation during a post deposition anneal is investigated. Our results indicate that SiN(x) induced hydrogen passivation is ...
    • Production Viability of Gallium Doped Mono-Crystalline Solar Cells 

      Crabtree, Geoffrey; Jester, Theresa L.; Fredric, Christian; Nickerson, Jeff; Meemongkolkiat, Vichai; Rohatgi, Ajeet (Georgia Institute of Technology, 2005-01)
      Results of efforts at Shell Solar to implement the use of gallium dopant as a commercial solar cell production process are presented. Both small area cell results and production related activities and results are discussed. ...
    • Rapid and Accurate Determination of Series Resistance and Fill Factor Losses in Industrial Silicon Solar Cells 

      Bowden, S.; Rohatgi, Ajeet (Georgia Institute of Technology, 2001-10)
      Lower than ideal fill factors (FF) are caused by parasitic series (R(s)) and shunt (R(shunt)) resistances, and non-ideal diode properties. The challenge is to quantify the FF losses quickly, simply and without ambiguity. ...
    • Rapid Photo-Assisted Forming Gas Anneal (FGA) for High Quality Screen-Printed Contacts for Silicon Solar Cells 

      Ebong, Abasifreke; Hilali, Mohamed M.; Rohatgi, Ajeet (Georgia Institute of Technology, 2000-09)
      Formation of low-cost high-quality contacts is the key to cost-effective silicon solar cells. Screen-printing is widely used in Industry because it is simple, low-cost and rapid. However, cost and throughput gains are ...
    • Rapid Thermal Processing for Front and Rear Contact Passivation 

      Bowden, S.; Kim, Dong Seop; Honsberg, Christiana B.; Rohatgi, Ajeet (Georgia Institute of Technology, 2002-05)
      Rapid firing processes are well known to allow improvements in solar cell contacts, particularly for the rear contact. Previous results characterizing the quality of a rear aluminum-alloyed back surface field have measured ...
    • Rapid Thermal Technologies for High Efficiency Silicon Solar Cells 

      Ebong, Abasifreke; Cho, Y. H.; Hilali, Mohamed M.; Rohatgi, Ajeet; Ruby, D. S. (Georgia Institute of Technology, 2001-06)
      This paper shows that rapidly formed emitters (≤ 6 min) in a conveyor belt furnace or 3 minutes in an RTP system, in conjunction with a screen-printed (SP) RTP Al-BSF and passivating oxide formed simultaneously in 2 minutes ...
    • Record High Efficiency Screen-Printed Belt Co-Fired Cells on Cast Multi-Crystalline Silicon 

      Upadhyaya, A. D.; Sheoran, Manav; Rohatgi, Ajeet; Matthei, Keith (Georgia Institute of Technology, 2004-06)
      Record-high efficiency screen-printed 4 cm(2) solar cells were achieved on HEM and Baysix cast multi-crystalline silicon. These cells were fabricated using a simple, manufacturable process involving POCl3 diffusion for a ...
    • Record-High-Efficiency Solar Cells on Multicrystalline Materials Through Understanding and Implementation of RTP-Enhanced SiNx-induced Defect Hydrogenation 

      Rohatgi, Ajeet; Kim, Dong Seop; Yelundur, Vijay; Nakayashiki, Kenta; Upadhyaya, A. D.; Hilali, Mohamed M.; Meemongkolkiat, Vichai (Georgia Institute of Technology, 2004-01)
      This paper presents results on five record-high-efficiency 4 cm(2) solar cells on three different multicrystalline silicon materials through effective hydrogen passivation of bulk defects during cell processing. Silicon ...
    • RIE-Texturing of Multicrystalline Silicon Solar Cells 

      Ruby, D. S.; Zaidi, S. H.; Narayanan, S.; Damiani, Benjamin Mark; Rohatgi, Ajeet (Georgia Institute of Technology, 2001-06)
      We developed a maskless plasma texturing technique for multicrystalline silicon (mc-Si) cells using Reactive Ion Etching (RIE) that results in higher cell performance than that of standard untextured cells. Elimination of ...
    • Screen-Printed Back Surface Reflector for Light Trapping in Crystalline Silicon Solar Cells 

      Ristow, Alan; Hilali, Mohamed M.; Ebong, Abasifreke; Rohatgi, Ajeet (Georgia Institute of Technology, 2001-10)
      Evaporated metal back surface reflectors have been shown to yield high values of internal rear reflectance, and are particularly eff ective when combined with a thin dielectric layer between the silicon and the metal. ...
    • Self-Aligned Self-Doping Selective Emitter for Screen-Printed Silicon Solar Cells 

      Rohatgi, Ajeet; Hilali, Mohamed M.; Meier, D. L.; Ebong, Abasifreke; Honsberg, Christiana B.; Carroll, A. F.; Hacke, P. (Georgia Institute of Technology, 2001-10)
      A self-aligned selective emitter for screen-printed solar cells is described in which phosphorus dopant is incorporated into a silver paste and diffused into the silicon. This produces an ohmic contact on 70-100 Ω/􀂆 emitter ...
    • Self-Doping Contacts and Associated Silicon Solar Cell Structures 

      Meier, D. L.; Davis, H. P.; Shibata, A.; Abe, T.; Kinoshita, K.; Bishop, C.; Mahajan, S.; Rohatgi, Ajeet; Doshi, P.; Finnegan, M. (Georgia Institute of Technology, 1998-07)
      Contacts to <111> Si which are self-doping and self-aligning were investigated. Such contacts are applicable both to conventional cell structures as selective emitters and to more demanding structures such as interdigitated ...
    • String Ribbon Silicon Solar Cells with 17.8% Efficiency 

      Kim, Dong Seop; Gabor, A. M.; Yelundur, Vijay; Upadhyaya, A. D.; Meemongkolkiat, Vichai; Rohatgi, Ajeet (Georgia Institute of Technology, 2003-05)
      We have fabricated 4 cm(2) cells on String Ribbon Si wafers with efficiencies of 17.8% using a combination of laboratory and industrial processes. These are the most efficient String Ribbon devices made to date, demonstrating ...
    • Study of Direct PECVD SiN(x)-Induced Surface Emitter and Bulk Defect Passivation in P-Type Silicon Solar Cells 

      Upadhyaya, A. D.; Sheoran, Manav; Rohatgi, Ajeet (Georgia Institute of Technology, 2005-01)
      This paper shows that direct low-frequency (LF) deposition of SiN films at 425 °C by PECVD followed by a conventional screen-printed contact firing cycle is more effective than a high-frequency (HF) SiN film deposited at ...
    • Understanding and Development of Ag Pastes for Silicon Solar Cells with High Sheet-Resistance Emitters 

      Hilali, Mohamed M.; Rohatgi, Ajeet; Khadilkar, Chandra; Kim, Steve; Pham, Tung; Salami, Jalal; Shaikh, Aziz; Sridharan, Srinivasan (Georgia Institute of Technology, 2004-06)
      The effect of different properties of the inorganic constituents of the Ag paste used for the front metal grid is investigated for high sheet-resistance emitters. Our results show that both glass frit chemistry and Ag ...
    • Understanding of the RTP-assisted Reduction of Hydrogen Dissociation from Defects in EFG Si 

      Nakayashiki, Kenta; Kim, Dong Seop; Rohatgi, Ajeet; Bathey, Bala R. (Georgia Institute of Technology, 2004-01)
      This paper shows that very short, one second, firing of screen-printed Al on the back and SiN(x) anti-reflection coating on the front can significantly enhance the bulk lifetime in EFG Si through SiN(x)-induced hydrogenation ...
    • Understanding the Role of Forming Gas on the Screen-Printed Crystalline Silicon Solar Cell Front Grid 

      Ebong, Abasifreke; Kim, Dong Seop; Yelundur, Vijay; Upadhyaya, V.; Rounsaville, Brian; Upadhyaya, A. D.; Tate, K.; Rohatgi, Ajeet (Georgia Institute of Technology, 2006-09)
      In this paper we report on the role of forming gas anneal on the fill factor of a small area cell and efficiency loss due to scaling the cell area. Solar cells that are under-fired and those fired at the optimum peak firing ...