Title :
Characterization of epitaxial film silicon solar cells grown on seeded display glass
Author :
Young, David L. ; Grover, Sachit ; Teplin, Charles ; Stradins, Paul ; LaSalvia, Vincenzo ; Chuang, Ta-Ko ; Couillard, J. Greg ; Branz, Howard M.
Author_Institution :
Nat. Renewable Energy Lab., Golden, CO, USA
Abstract :
We report characterization of epitaxial film crystal silicon (c-Si) solar cells with open-circuit voltages (Voc) above 560 mV. The 2-um absorber cells are grown by low-temperature (<;750 °C) hot-wire CVD (HWCVD) on Corning® EAGLE XG® display glass coated with a layer-transferred (LT) Si seed. The high Voc is a result of low-defect epitaxial Si (epi-Si) growth and effective hydrogen passivation of defects. The quality of epitaxial growth by HWCVD on seeded glass substrates depends on the crystallographic quality of the seed and the morphology of the growth surface. Complete heterojunction cells consist of glass/c-Si LT seed/ epi n+ Si:P/epi n- Si:P/intrinsic a-Si:H/p+ a-Si:H/ITO. Similar devices grown on electronically `dead´ n+ wafers have given Voc ~ 630 mV and ~8% efficiency with no light trapping features. Here we study the effects of the seed surface polish on epi-Si quality, how hydrogenation influences the device character, and the dominant junction transport physics.
Keywords :
elemental semiconductors; epitaxial growth; hydrogen; hydrogenation; passivation; semiconductor thin films; silicon; solar cells; Corning EAGLE XG display glass; H; HWCVD; Si; Si:H; Si:P; absorber cells; crystallographic quality; defects passivation; epitaxial film solar cells; epitaxial growth; heterojunction cells; hot-wire CVD; hydrogenation; junction transport physics; light trapping; open-circuit voltages; size 2 mum; temperature 750 C; voltage 560 mV; voltage 630 mV; Epitaxial growth; Glass; Rough surfaces; Silicon; Substrates; Surface roughness; epitaxial layers; glass; silicon; solar energy;
Conference_Titel :
Photovoltaic Specialists Conference (PVSC), 2012 38th IEEE
Conference_Location :
Austin, TX
Print_ISBN :
978-1-4673-0064-3
DOI :
10.1109/PVSC.2012.6317952