Photoluminescence Characterization of Hydrogenated Nanocrystalline/Amorphous Silicon

The 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 (similar to 600 degrees C). Two predominant luminescence peaks are observed at similar to 0.95 eV and similar to 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/cm(2) excitation intensity. Annealing the nc-Si/a-Si: H mixture brings out a new low energy peak, centered at similar to 0.70 eV, and which we believe to be due to oxygen defects.