Microstructure analysis of n-doped μc-SiOx:H reflector layers and their implementation in stable a-Si:H p-i-n junctions

Microcrystalline hydrogenated silicon oxide (μc-SiO_x:H) has been studied as back reflector layers to increase the performance of thin-film silicon solar cells. The nature of the heterogeneous microstructure of μc-SiO_x:H layers has been studied in more detail. Raman Spectroscopy has been used to study the properties of crystalline silicon grains whereas FTIR spectroscopy has been used to study the amorphous silicon-oxide tissue. The correlations between deposition parameters, the material properties of μc-SiO_x:H and solar cell performance are discussed. Various μc-SiO_x:H/Ag back reflectors have been integrated in a-Si:H single junction cells resulting in improved light trapping in the thin film silicon resulting in an initial efficiency of 10.8%. The best stable efficiencies are achieved for cells with an intrinsic a-Si:H film of around 200 nm.