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.

Design and Develop a Photo Detector (CdS/Si)

In this study, CdS films prepared using the technique of pyrolysis spray at the glass and Si wafer with a thickness of 300 nm using Cadmium Acetate Cd (CH3COO)2 middot;2H2O with purity of 99.6% and Thiourea (CS(NH2)2) with purity 99.6%. These compounds are used as the sourced materials of Cd+2 and S2 ions, respectively for the CdS films formation. The films were annealed at different temperatures (400, 500, and 600 0C), then the effect of annealing on its properties was studied. The highquality films were obtained as evident using XRD analysis. Xray diffraction analysis for all CdS films was polycrystalline with cubic and hexagonal wurtzite structure with preferential orientation in the H (002) and C (111) direction. It is difficult to distinguish between them, after hightemperature process from 400 0C to 6000C, new peaks of the hexagonal structure appeared. This phenomenon was thought to be the phase change of CdS thin film by heat treatment as well as the increasing of intensity of H (002) and decreases in full width at half maxima (FWHM) the grains size with annealing. The CdS photodetector and the spectral response of CdS/Si junction was studied. The maximum value of responsivity occurred at a wavelength of 500 nm to 560 nm. The maximum values of D* and eta; at Ta equal to 500 0C. Whereas, they increase and shift to higher wavelength with the increase of Ta. It has been observed that the best spectral response occurs when the annealing temperature equal to 500 0C, therefore, is essential to say that this value of Ta was the optimum condition for prepared CdS photoconductive detector.