Designing and developing a photo detector (CdS/Si)

Cadmium sulfide (CdS) thin films were prepared using the technique of spray pyrolysis included the glass and Si wafer (300 nm thick) using Cadmium Acetate Cd (CH3COO)2ꞏ2H2O and Thiourea (CS(NH2)2). These compounds are used as the control materials of Cd+2 and S-2 ions, respectively. The films were annealed at different temperatures (400, 500, and 600oC). The high-quality films were obtained using XRD analysis. X-ray diffraction analysis for all CdS films was polycrystalline with a cubic and hexagonal structure of H (002) and C (111). It is difficult to distinguish between them, after the temperature from 400 oC to 600 oC, new peaks of the hexagonal structure appeared. The maximum value of responsivity occurred at a wavelength of 500 to 560 nm. It has been observed that the best spectral response occurs when the annealing temperature is 500oC. The highest peak have obtained within the wavelengths between 500- 560 nm signifies the greatest response and the greatest quantitative and qualitative detection efficiency as it ranges with an annealing temperature.