Transport Properties of Polycrystalline Films of Cadmium-Telluride

The spectral variation of the optical reflectance, transmittance, and the short circuit photomagnetoelectric effect current was investigated for polycrystalline films of CdTe. The dependence of the PME current on the absorption coefficient was used to determine the excess carrier diffusion length, the effective Hall mobility, and obtain an estimate of the diffusion length lifetime for the samples. The experimental results support the proposal that these films represent examples of trap-dominated relaxation semiconductors. Correlation with studies of the UV reflectance and X-ray diffraction, suggests that the concentration of native defects present in high-resistivity CdTe films is enhanced by the presence of the hexagonal (wurtzite) phase.