Boron doped amorphous silicon carbide/nanocrystalline silicon (p-type a-SiC/nc-Si) hybrid window layer has a great potential to improve the solar cells performance for its high optical band gap, carrier mobility and doping efficiency. Thin ( <30 nm) p-type a-SiC/nc-Si hybrid films have been successfully deposited by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) from silane-methane gas mixtures at a low temperature of 150 degrees C. Raman, FT-IR and HRTEM measurements were employed to investigate the structural characteristics of hybrid structure films. High quality p-type a-SiC/nc-Si hybrid window layer with controllable nano-sized silicon crystals embedded in amorphous silicon carbide matrix was obtained. Hybrid structure films with high values of optical band gap (similar to 2.2 eV) and sigma(d) (similar to 10(-3) S/cm) were achieved in high hydrogen dilution conditions with optimized doping concentrations. Applying high quality p-type window layers and intrinsic a-Si layers, both high open circuit voltage ( >0.96 V) and high quantum efficiency values at short wavelengths were achieved for n-i-p type a-Si single junction solar cell. Meanwhile, the efficiency of the amorphous silicon and silicon-germanium (a-Si/a-SiGe) double junction solar cell was significantly improved to 11.8% by incorporating p-type a-SiC/nc-Si hybrid structure window layer. (C) 2013 Elsevier B.V. All rights reserved.