The spectral responsivity enhancement for gallium-doped CdO/PS heterojunction for UV detector

Abstract

Despite the large number of studies on CdO, it was until very recently the system properties Ga-doped CdO/PS was not recognize well. In this paper, photodetector of Ga-doped CdO/Si and Ga-doped CdO/PS nanocrystalline with different Ga ratios (0, 3, and 7%) have been prepare by spray pyrolysis deposition (SPD). The structural properties of un doped CdO and doped films were characterized by X-ray diffraction, which refer to that the CdO thin films have cubic structure. The energy gap of un doped film and doped with Ga increased from 2.5 to 3.56 eV with increasing Ga ratios. I-V characteristics of Ga-doped CdO/PS photodiodes without illumination exhibit good rectification behavior compared with Si substrate, and the value of photocurrent increased with Ga ratios increased. The spectral responsivity curves (A/W) of all devices prepared allow acceptable sensitivity response in the visible wavelength region, and shifted toward ultra-violet region with increase Ga ratios.