Functionalization of doped ZnO through solution route synthesis: a study using spectroscopy & density of states

ZnO is one of the widely studied materials for multidimensional applications, viz. semiconductor material, catalysts, solid-state devices, etc. The primary functionalization is carried out by doping the required element (s) within the ZnO matrix, which can exist in either zinc blend or the wurtzite form. The present research reports synthesis of ZnO doped by Cr, Y, and Eu at two dopant concentrations. The synthesis technique is optimized using dual fuels during solution auto combustion synthesis. Detailed analysis of X-ray diffraction study reveals a comparative analysis of the peak area and FWHM magnitude. The influence of the doping element on the ZnO is studied in terms of UV and photoluminescence spectra. The highest bandgap of 3.08 eV is reported with Eu as the dopant within ZnO compared to Y, which shows lower bandgap energy of 2.44 eV. The density of states study of ZnO is found to be continuous with a significant nodal region within -3.4 to -2.4 eV. However, in the doped systems, irrespective of the dopant, nodal regions are more with specific band regions in the ZnO-Y/ZnO-Eu system. Irrespective of dopant type, doping within ZnO significantly influences the states in the conduction band.