Improvement of photoconductivity in Silicon Tin (SiSn) thin films

Hydrogenated-amorphous silicon tin alloy (a-SiSn (C:H)) films have been prepared by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) technique. We present investigations of the absorption and photoconductivity characteristics of a-SiSn(C:H) thin films as a function of the tin concentration, which could be a pivotal feature for the bottom solar cell development. We demonstrate that the photoconductivity is significantly improved by the film growth under enhanced hydrogen dilution. The results suggest that the hydrogen dilution plays an important role in development of high quality a-SiSn(C:H) photosensitive thin films.

► Fabrication of a-SiSn(C:H) films by using PECVD technique. ► Improvement of photoconductivity in a-SiSn(C:H) films by the hydrogen flow. ► Reduction of incorporated Sn4 + and Sn2 + sites with atomic hydrogenation.