Optical and compositional properties of a-Si:H / transparent conductive oxide interfaces

Films of hydrogenated amorphous silicon were deposited at different temperatures on films of transparent conductive oxides (TCO's) (tin oxide and indium tin oxide) having different composition, thickness, and resistivity. Microcompositional analysis was performed by secondary ion mass spectroscopy to measure the microdistribution of Si, Sn and In. The optical properties of single a-Si:H films and a-Si:H films deposited on TCO were determined from measurements of transmittance and reflectance. The optical constants, refractive index, absorption coefficient, and optical band gap of single a-Si:H films are different from those of the same films deposited on TCO. The amount of Sn and In in the a-Si:H layer were found to depend on the deposition temperature and on the characteristics of the TCO and to be correlated with the optical properties.