Study of Optoelectronic Properties CdS-Si Heterojunction Prepared by Chemical Bath Deposition Method

CdS-Si heterojunction detector has been prepared by chemical bath deposition method . Structure properties of these films was characterized by X-ray diffraction .CdS films deposited have polycrystalline structure cubic(zinc blende) and hexagonal. The average grain size is 45 nm .The optical properties of the CdS films have highly transmittance in visible region of spectrum and reach to more than 80 % with a wide band gap of 2.44 eV .Electrical properties of CdS-Si heterojunction have been investigated. The I-V characteristics under dark condition depict that good rectification behavior and exponential relationship for forward current biasing. The C-V measurements have shown that the heterojunction were of abrupt type and the build-in potential equal to 1.75V. The optoelectronic characteristics shows that CdS-Si detector has good spectral responsivity in the visible and the near infrared and show high sensitivity, in comparison with the conventional p-n silicon detectors