Schottky Barrier as Photodetector Based on Nanostructured Cd _x Zn_1-x S along with Switchable Photocurrent Generation

In this report, Schottky barrier devices (SBDs) have been fabricated based on CdS nanorods (NRs), ZnS nanoparticles (NPs), and Cd_0.5Zn_0.5S (NPs + NRs) using a cost-effective spin coating technique with the use of metallic "Ag". Photodetection properties based on fabricated Schottky barriers of CdS NRs/Ag, Cd_0.5Zn_0.5S (NPs+NRs)/Ag and ZnS NPs/Ag have been studied. Before device fabrication, a simple chemical precipitation method has been used for the growth of CdS NRs, Cd_0.5Zn_0.5S (NPs + NRs) and ZnS NPs. Formations of nanostructures have been observed through HRTEM and FESEM. The structural and optical analyses of the grown nanostructures have been computed from XRD, XPS, UV-vis spectra and Raman studies. The responsivity, detectivity,and response time of the three photodetectors based on SBDs have been measured and compared. The photodetectors exhibited a high rectification ratio up to 10⁶ within ±1 V in the dark and a sharp photoresponse behavior under light illumination. Photoresponse analysis showed that a photodetector based on SBD of CdS NRs was highly sensitive to light illumination with detectivity ≈2.75 × 10⁵ jones and responsivity ≈2.2 × 10^-6 A/W. The above parameters were reduced for photodetector based on SBD of ZnS NPs. Also, switchable photocurrent generation have been observed for three photodetectors. The photoresponse rise/fall times of CdS NRs based SBD was ≈187/194 ms and showed fast response speed compared to other two photodetectors based on SBDs.