Photoluminescence Characterization of Hydrogenated Nanocrystalline/Amorphous Silicon

Abstract

AbstractThe photoluminescence in a nc-Si/a-Si:H mixture has been investigated at varying excitation intensities, and temperatures We have also observed changes in the luminescence spectra, which are induced by sequential annealing at temperatures below the a-Si:H crystallization temperature (˜ 600°C). Two predominant luminescence peaks are observed at ˜ 0.95 eV and ˜ 1.30 eV, which are attributed to band tail-to-band tail transitions near the nc-Si grain boundaries and in the a-Si:H bulk, respectively. The 0.95 eV band saturates approaching 500 mW/cm2 excitation intensity. Annealing the nc-Si/a-Si:H mixture brings out a new low energy peak, centered at ˜ 0.70 eV, and which we believe to be due to oxygen defects.