Substrate Temperature Influence on Properties of Amorphous Silicon-Germanium Thin Films Prepared by RF-PECVD

Amorphous silicon-germanium films were prepared by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) on the glass. The structural characteristics, deposition rate, optical band gap and photosensitivity of the silicon-germanium thin films had been investigated at different substrate temperatures. It indicated that the substrate temperature had nothing to do with the crystallization degree of the thin films. However with the substrate temperature increasing, the deposition rate decreased. The optical band gap and the photosensitivity of the thin films both increased first and fell later as the substrate temperature increasing. At 240°C, the optical band gap was the largest. The photosensitivity was the biggest at the temperature of 160°C. Changing the substrate temperature could change the deposition rate, optical band gap and photosensitivity, which could be a great help in a-Si/a-SiGe/a-SiGe stacked solar cells.