Photo and electroluminescence of a-Si:Er:H

Trivalent erbium (Er3+) presents a characteristic intra 4f optical transition I-4(13/2) --> I-4(15/2) 1.54 mu m when incorporated in several solid hosts. Hydrogenated amorphous silicon (a-Si:H) is a good candidate as a host for applications in optical communications and photonic integration. We have studied Er3+ photo and electroluminescence in a-Si:H prepared by co-sputtering from a silicon target partially covered with metallic erbium chunks. Since the presence of oxygen impurities enhances the luminescence intensity, we studied the influence of oxygen added to the sputtering gas on the material properties. We found that oxygen reduces the erbium incorporation into the films. We obtained samples presenting 1.54 mu m photoluminescence as deposited for a wide range of erbium concentrations. Maximum room-temperature photoluminescence efficiency is obtained for samples that contain similar to 1% [O]/[Si] concentrations. The temperature quenching is small, mainly due to the temperature dependence of the luminescence lifetime. Room temperature electroluminescence at 1.54 mu m was observed in reverse biased Si/a-Si:Er:O:H/Al structures.