Silicon-Germanium alloys have been prepared in an evacuated fused silica tube, and by thermal evaporation amorphous Si1-x,Ge-x:H thin films were deposited at different preparation conditions such as deposition temperature (T,), dopant concentration of aluminum (Al) and arsenic (As) and Ge content (x). Fourior transform infrared (FT-IR) investigations showed the existence of all the expected stretching and bending modes of (Si-H)(n) and (Ge-H)(n). The X-ray photoemission spectroscopy (XPS) exhibited the existence of oxygen:carbon and hydrogen atoms on the Si-Ge surface which led to a shift in Si-2p and Ge-3p core level for pure and doped a-Si1-xGex:H thin films with aluminum and arsenic. (C) 2002 Elsevier Science Ltd. All rights reserved.