Defects assisted photosensing and dye degradation of Ni/Ga co-doped ZnO: A theory added experimental investigation

Abstract

Ni or Ga doping is well studied in literature. However, a Ga/Ni co-doped ZnO brings in complex competing mechanisms of electron mobility and electron localization. A sol-gel prepared solid solution of Ga/Ni co-doped ZnO with hexagonal wurtzite structure (P63mc space group) is studied in detail to correlate the electronic properties to the structure of the materials. Lattice strain studies correlated to these changes in the electronic properties. The drastic reduction in native defects was detailed using the photoluminescence study of Ni/Ga co-doped ZnO. Lattice and phonon studies were used to explain the lattice strain in the ZnO lattice. The % Sensitivity of UV (290 nm), blue (450 nm), green (540 nm) and red (640 nm) wavelengths were tested and correlated with the defects. Additionally, the photo-catalytic dye degradation of toxic methylene blue was investigated and explained with changes in carrier concentration and mobility. The reason behind the conductive parameters was examined theoretically and a possible reason was found in terms of changes in electron localization due to increasing Ni/Ga concentration.