Hydrogen related defect complexes in ZnO nanoparticles

Abstract

Hydrogen related local vibrational modes (LVMs) of ZnO nanoparticles have been studied using Fourier transform infrared spectroscopy and Raman spectroscopy in as prepared and high temperature annealed samples. The obtained experimental results confirm the presence of cationic vacancies (VZn) in addition to unintentional hydrogen doping and their complex defects such as VZn–Hi and VZn–HO. After high temperature annealing, hydrogen related LVMs and multiphonon modes disappear. The presence of these complex defects determines the nonradiative and multiphonon recombination processes in the band gap of ZnO due to carrier trapping at deep levels.