The performances of p-i-n amorphous silicon germanium (a-SiGe:H) solar cell modules were investigated post annealing at different temperatures. When the annealing temperature is 190 degrees C, the best performance of solar cell modules is obtained. The efficiency of solar cell modules is improved from 5.11% to 7.91%. The enhancement in quantum efficiency spectra at long wavelength post annealing may be attributable to there being significantly less absorption in intrinsic layer. The microstructural properties of the a-SiGe: H thin films are investigated post annealing at different temperatures. The results show that the low temperature annealing process leads to the improvement in the film microstructure. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.