Title :
Staebler-Wronski defects: Creation efficiency, stability, and effect on a-Si:H solar cell degradation
Author_Institution :
Nat. Center for Photovoltaics, Nat. Renewable Energy Lab., Golden, CO, USA
Abstract :
The creation efficiency of Staebler_Wronski (SW) defects, their thermal stability, and their effect on degradation of a-Si:H solar cells is discussed with emphasis on hydrogen bonding configurations. In device-quality a-Si:H films prepared by different methods, creation efficiency of SW defects is remarkably similar. The increased stability against SW degradation in hydrogen-diluted material is mainly due to low thermal stability of SW defects. The SW defect creation is, however, reduced in films with lower hydrogen content prepared by annealing to elevated temperatures. While defect thermal stability strongly affects electron mobility-lifetime product in a-Si:H films, it has little effect on extent of the degradation in cells. This suggests that carrier capture coefficient into defects are governed by their charge state. Thermal stability of SW defects is likely governed by numerous, pre-existing, paired hydrogen configurations nearby the defects that serve as an annealing source for the defects, as suggested by tritiated a-Si:H experiments.
Keywords :
Staebler-Wronski effect; elemental semiconductors; hydrogen bonds; solar cells; thermal stability; Staebler-Wronski defects; hydrogen bonding configurations; paired hydrogen configurations; solar cell degradation; thermal stability; Annealing; Degradation; Films; Laser stability; Photovoltaic cells; Temperature measurement; Thermal stability;
Conference_Titel :
Photovoltaic Specialists Conference (PVSC), 2010 35th IEEE
Conference_Location :
Honolulu, HI
Print_ISBN :
978-1-4244-5890-5
DOI :
10.1109/PVSC.2010.5614549