Structural and optical properties of In-doped CdS nanostructures: A comprehensive study

This research offers a comprehensive exploration of the effects of In-doping on the characteristics of CdS nanopowders (NPs). The structural and morphological properties of In-doped CdS nanostructures were investigated, revealing significant changes induced by In-doping. X-ray diffraction (XRD) analysis verified the formation of CdS phase. Determination of crystallite size (D) demonstrated a decrease from 27.0 nm for undoped CdS to 23.0 nm for CdS doped with 12 % In-doped. Field-emission scanning electron microscopy (FESEM) imaging showed grain-like structures with sizes of 20-35 nm, showing variations in particle size distribution with increasing In-dopant concentration. Photoluminescence (PL) analysis illustrated changes in PL intensity and emission peak wavelengths due to In-doping. PL intensity decreased after In-doping. Additionally, a blue-shift in emission peak wavelengths indicated changes in the bandgap energy of CdS induced by In-doping. UV-Vis spectroscopy assessed the optical properties, revealing shifts in absorption and transmission spectra du to Indoping. In-doping enhanced absorption within the 400-500 nm range while decreasing absorption within 600-1000 nm. Transmission spectra displayed increased transparency after In-doping, attributed to modifications in band structure and morphology. Reflectance spectra initially increased with In-dopant concentration within 400-500 nm, followed by a decrease, suggesting alterations in electronic and structural properties. Estimation of band gap energy (Eg) unveiled an increase in Eg for In-doped CdS nanostructures compared to undoped CdS, likely due to reduced crystallite size and the Burstein-Moss effect induced by In-dopant ions. Raman analysis revealed a shift in peak positions and changes in intensity after In-doping, with a decrease in the 2LO/LO ratio indicating a deterioration in crystalline quality after In-doping. Overall, this comprehensive investigation provides valuable insights into the structural, morphological, optical, and electrical properties of In-doped CdS nanostructures, pivotal for their promising applications in optoelectronic devices and photovoltaics.