The effect of crystallinity of p window layers on the structural and electrical properties of intrinsic μc-Si:H and superstrate solar cells

Effects of crystallinity of the p window layers in the pin solar cells having hydrogenated microcrystalline silicon (μc-Si:H) films as an absorber layer on solar cell performance are investigated through the evaluation of the photovoltaic characteristics of solar cells prepared by varying the gas ratio of SiH₄/H₂ during the p layer deposition. By Raman scattering spectroscopy analysis, it is observed that the volume fraction of crystalline/amorphous phases (X_c) of p layers decreases from 31.0% to 5.1% with increasing the SiH₄ concentration from 0.2 to 1.0 sccm at fixed H₂ of 180 sccm. Depending on the X_c of the p layers, the solar cell performance is affected significantly, where the solar cells with the p window layers of low X_c represent good photovoltaic characteristics, namely high open circuit voltage (V_oc) and short circuit current density (J_sc). Some experimental results and discussion about relationship between crystalline structure of p layers and performance of μc-Si:H solar cells will be presented briefly in this paper.