Development of doped silicon oxide based microcrystalline material as a potential candidate for cost-effective and reliable back reflector layer (BRL) for single junction solar cells is discussed in this article. Phosphorus doped mu c-SiOx:H layers with a refractive index similar to 2 and with suitable electrical properties were fabricated by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) technique, using the conventional capacitively coupled reactors. Optoelectronic properties of these layers were controlled by varying the oxygen content within the film. The performance of these layers as BRL have been investigated by incorporating them in a single junction amorphous silicon solar cell and compared with the conventional ZnO:Al based reflector layer. Single junction thin film a-Si solar cells with efficiency similar to 9.12% have been successfully demonstrated by using doped SiO:H based material as a back reflector. It is found that the oxide based back reflector shows analogous performance to that of conventional ZnO:Al BRL layer. The main advantage with this technology is that, it can avoid the ex-situ deposition of ZnO:Al, by using doped mu c-SiO:H based material grown in the same reactor and with the same process gases as used for thin-film silicon solar cells. (C) 2013 Elsevier Ltd. All rights reserved.