Boron-doped nanocrystalline silicon thin films for solar cells

This article reports on the structural, electronic, and optical properties of boron-doped hydrogenated nanocrystalline silicon (nc-Si:H) thin films. The films were deposited by plasma-enhanced chemical vapour deposition (PECVD) at a substrate temperature of 150 °C. Crystalline volume fraction and dark conductivity of the films were determined as a function of trimethylboron-to-silane flow ratio. Optical constants of doped and undoped nc-Si:H were obtained from transmission and reflection spectra. By employing p+ nc-Si:H as a window layer combined with a p′ a-SiC buffer layer, a-Si:H-based p–p′–i–n solar cells on ZnO:Al-coated glass substrates were fabricated. Device characteristics were obtained from current–voltage and spectral-response measurements.