Fabrication of heterojunction CdO/p-Si photodetectors and their electrical characterization

In this study, undoped Cd0, %0.2 Mn doped CdO, %6 Mn doped CdO and %10 Mn doped CdO thin films were deposited on Si substrate. Films were produced by Sol-Gel method at room temperature. Surface properties of the samples were investigated by using atomic force microscopy (AFM). AFM results indicated that CdO formed in the granular structure on the substrate and spread homogeneously on the substrate surface. To assess the electrical properties of the thin films Current – Voltage (I-V), Capacitance – Voltage (C-V), Current – Time (I-t) measurements were performed in different illumination intensities. It was also seen that samples show corrective properties. It was evidenced that the photocurrent of photodiodes shows increasing properties with increasing illumination intensities. When the light source was shut off, the photocurrent properties return to the initial state. It was also noted that photodiodes show decreasing characteristics with increasing frequency. Optical properties of the thin films were measured by using UV-vis spectrophotometry and band gap energies were calculated using reflectance spectrum.