Fabrication and Study Characteristics Of CdS/Si Heterojunction Detector by CBD Technique

Abstract

In the present work, fabrication and characterization detector CdS/Si heterojunction. The CdS thin film depositing on glass substrate and silicon Wafers by chemical bath deposition(CBD) technique. Structure of these films was characterized by X-ray diffraction ,which show that of CdS films deposited have polycrystalline structure cubic(zinc blende) and hexagonal (diamond) and the grain size is 45 nm . The optical properties were studied by transmission spectra where found that for CdS films have highly transmittance in visible region of spectrum and reach to more than 80 % with wide band gap of 2.44 eV is a promising material to be used in photovoltaic devices as solar cells and detectors .Electrical properties of CdS/Si heterojunction have been investigated. The I-V characteristics of 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 1.75V. The optoelectronic characteristics shows the CdS/Si detector has good spectral responsivity in visible and NIR with higher peak responsivity at 800 nm were found 0.26 A/w .The maximum quantum efficiency was found to be (60%) at (800 nm) wavelength.