Structural study of p-type μc-Si layer for solar cell application

It is important for solar cell application to study the opto-electrical properties of very thin (<30 nm) p-type microcrystalline silicon (μc-Si(p)) layers deposited on amorphous silicon (a-Si) or a-Si based alloy layers. The properties of very thin pc-Si(p) layers were studied by using a p-i-n single junction cell structure. For evaluation of μc-Si(p) layer, we carried out such measurement as Raman scattering spectra, sheet resistance and transmission electron microscopy. The structure of μc-Si(p) layer depends on the substrate temperature (T s ). The μc-Si layer directly grows on the underlying amorphous layer at T s = 85°C. At T s = 150°C, on the other hand, the layer has amorphous phase in the initial half zone and becomes crystalline phase in the latter half. At T, < 85°C, μc-Si grains have columnar or spherical structures with voids between grains.