Evaluation of Hydrogenated Amorphous Silicon Oxide Photo-Absorber from Quantum Efficiency in Thin-Film Solar Cell by Fourier Transform Photocurrent Spectroscopy

Abstract

We demonstrated evaluation of sub-gap state and gap-state defect in hydrogenated amorphous silicon oxide (a-SiO_X:H) photo-absorber within solar cell structure from internal quantum efficiency (IQE) measured by Fourier transform photocurrent spectroscopy (FTPS). In IQE spectra for a-SiO_X:H thin-film solar cells, exponential tail and IQE corresponding to gap-state defect was observed. We also investigated light-induced degradation in a-SiO_X:H photo-absorber within solar cell structure by FTPS. IQE related to gap-state defect increased and conversion efficiency decreased by light irradiation, which corresponds to light-induced degradation. Urbach energy obtained from IQE spectra increased by light irradiation.