Enhanced self-powered and visible-range photodetector performance of Ag2S nanostructures by Cu concentrations

Abstract

In the present research, silver sulfide (Ag2S) nanostructures were grown using the sonochemical method. The effect of copper (Cu) dopant in different concentrations was investigated on the physical and electrical properties, and then their performance as photodetectors were evaluated. It was found that Cu doping shifted the XRD peaks of Ag2S to higher angles and increased the crystallite size. FESEM images showed that adding Cu in different concentrations increased the size of Ag2S nanostructures, while the spherical shape of Ag2S nanostructures did not change. XPS analysis confirmed the formation of the Ag2S phase, being consistent with XRD results and incorporation of Cu atoms in substitution positions in the crystalline structure. The study of optical properties indicated that the absorption intensity of Cu-doped Ag2S nanostructures decreased compared to the un-doped sample. Electrical analyses revealed that adding Cu concentrations increased the density of electrical carriers. The charge transfer process was studied using the current-voltage curve under different conditions. The evaluation of optoelectronic properties also demonstrated that the presence of Cu concentrations improved the quality parameters of Ag2S nanostructures as a self-powered photodetector in the visible-range wavelengths.