Nanocrystalline Silicon Films with High Conductivity Prepared by Hot Wire Chemical Vapor Deposition

Abstract

Nanocrystalline silicon (nc-Si:H) grown by hot-wire chemical vapor deposition (HWCVD). We report on the effects of B2H6 doping ratio on the microstructural and optoelectrical properties of the p-type nc-Si:H thin films grown by HWCVD at low substrate temperature of 200 °C. An attempt has been made to elucidate the boron doping mechanism of the p-type nc-Si:H thin films deposited by HWCVD and the correlation between the B2H6 ratio, crystalline volume fraction, optical band gap and dark conductivity. Characterization of these films from Raman spectroscopy revealed that the high conductive film consists of mixed phase of nanocrystalline silicon embedded in an amorphous network. A small increase in B2H6 doping ratio showed marked effect on film microstructure. At the optimal condition, high dark conductivity (8 S/cm) with high optical band gap (~2.0 eV) was obtained.