Optoelectronic properties of n-Ag2S nanotubes/p-Si heterojunction photodetector prepared by chemical bath deposition technique: An effect of deposition time

In this paper, silver sulfide (Ag2S) nanostructure film was prepared by chemical bath deposition (CBD) technique at different deposition times. The effect of deposition on the structural, optical and electrical properties of the Ag2S film is studied using x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive x-ray (EDX), transmission electron microscope (TEM), and UV-Vis spectroscopy. X-ray diffraction investigation shows that the deposited films are crystalline in nature with monoclinic structure. SEM results revealed that the film morphology depends on the deposition time. The film deposited at 10hr has mixed of agglomerated nanoparticles and nanotubes (NTs) morphologies. Transmission electron microscope (TEM) revealed that the average diameter of the nanotubes was 60nm.The optical properties show that the average optical transmission of the film decreases as the deposition time increase. The optical energy gap of the deposited films was found to vary from 1.8eV to 2.17 eV at room temperature depending on the deposition time. The figures of merit of the n-Ag2S/p-Si heterostructure photodetector such as dark and illuminated current-voltage, linearity, responsivity, and specific detectivity have been investigated as a function of deposition time. The maximum responsivity of the photodetector was around 0.5A/W at 850nm for photodetector prepared at deposition time of 10hr.