Physical Properties of Copper Nanoparticles Embedded Cadmium Sulfide Thin Films for Photovoltaic Applications

Abstract

Group II-VI semiconductors have countless significance in application of solar cells owing to their admirable opto-electrical properties. Current research is primarily focused on the optimization of cadmium sulfide (CdS) thin films with precise interest in solar cells applications. Closed space sublimation (CSS), a coating system has been settled and fabricated CdS thin films. Cadmium sulfide is transparent to the visible and infra-red regions of electromagnetic radiations. Current study concerned toward progress of CdS thin films to be used as a material for window layer using closed space sublimation technique. Thin films of CdS were fabricated on substrate of glass by closed space sublimation technique. The temperature of source during deposition was 450 ̊C and level of vacuum was in range of 10−2 mbar. As-deposited thin films were embedded with copper nanoparticles (Cu NPs) by spin coating for an optimized time at 2500rpm. The structural, morphological, electrical and optical analyses were done by using X-Ray Diffraction (XRD), Hall Measurement System, Atomic Force Microscopy (AFM) and Ultra violet visible (UV-VIS) Spectrophotometer respectively. The X-ray studies revealed a hexagonal structure with (111) as the preferred orientation. The average crystallite size was in the range of 50-57nm. CdS film transmittance reduced from 60% to 30% with increasing Cu NPs embedding. CdS films optical band gap of decreases from 2.37 to 2.25 eV with increasing Cu NPs embedding. Surface roughness was increased after Cu NPs embedding revealed from Atomic force microscopy (AFM). The conductivity increased from 5.49 × 101 to 1.17 × 103 (S.cm-1 ) owed to variation in the carrier concentration and with increase in value of mobility