Structure and electronic properties of μc-SiC:H for photovoltaic applications

Thin microcrystalline silicon carbide films (μc-SiC:H) were grown by the hot-wire deposition technique for implementation as a window layer into thin-film solar cells. The μc-SiC:H layers are characterised by a complex microstructure, which is dominated by crystalline columns with a high density of planar defects. In order to understand the relation between structural and optical properties of the μc-SiC:H layers, low-loss electron energy loss spectra were recorded. At heterogeneous grain boundaries and within the nucleation zone, which is characterised by a high density of smaller grains, we observe that the volume plasmon peak position shifts to lower energy compared to measurements within larger grains of the microcrystalline SiC:H film. This shift of the plasmon energy is attributed to a higher degree of disorder, which alters the electronic properties.