Indium doping effect on properties of ZnO nanoparticles synthesized by sol-gel method

Pure ZnO and indium-doped ZnO (In-ZO) nanoparticles with concentrations of In ranging from 0 to 5% are synthesized by a sol-gel processing technique. The structural and optical properties of ZnO and In-ZO nanoparticles are characterized by different techniques. The structural study confirms the presence of hexagonal wurtzite phase and indicates the incorporation of In3+ ions at the Zn2+ sites. However, the optical study shows a high absorption in the UV range and an important reflectance in the visible range. The optical band gap of In-ZnO sample varies between 3.16 eV and 3.22 eV. The photoluminescence (PL) analysis reveals that two emission peaks appear: one is located at 381 nm corresponding to the near-band-edge (NBE) and the other is observed in the green region. The aim of this work is to study the effect of indium doping on the structural, morphological, and optical properties of ZnO nanoparticles.