Extraction of carriers photogenerated at p type amorphous SiC window layer in amorphous Si solar cells

Abstract

The polarity of built-in electric field in p type amorphous SiC window layer originated from the band alignment with the front electrode, strongly affects carrier collection of amorphous Si solar cells. Additionally, it can be switched by reversing the surface band bending of transparent electrodes. Nitrogen incorporation at the surface of Al-doped ZnO modifies the surface band bending from the condition of carrier accumulation to that of carrier depletion; thereby quantum efficiency in short wavelength region is enhanced. The reversal of band bending also causes degradation of fill factors and open circuit voltages, which can be minimized to attain efficiency improvement. (C) 2010 American Institute of Physics. [doi:10.1063/1.3491164]