Microscopic origin of light-induced changes in hydrogenated amorphous silicon

Publisher Website
Google Scholar
Abstract
Light‐induced changes in the stretching mode absorption of Si‐H and Si‐H2 have been studied for hydrogenated amorphous silicon (a‐Si:H) films. The absorption below 2000 cm−1 decreases greatly, but a small change has been observed above 2100 cm−1. The magnitude of the overall change increases as the substrate temperature is lowered and little change is observed for a‐Si:H films deposited at above 200 °C. The change in boron‐doped a‐Si:H is small compared with the undoped film deposited at the same substrate temperature. Based on experimental results, it is suggested that the hydrogen in the bulk of a‐Si:H diffuses to the microvoids during light illumination.