Characteristics of point defects on the optical properties of ZnO: revealed by Al–H co-doping and post-annealing

Abstract

Understanding the influences of lattice defect evolution on the optical properties of ZnO is of significance. To clarify this, we adopted typical treatments on ZnO using Al–H co-doping and post-annealing, combined with comprehensive characterization (absorption spectrum, Raman scattering, photoluminescence, electronic paramagnetic resonance and positron annihilation). The results reveal that the visible luminescence can arise from the VO, VZn and AlZn–Oi defects, while the defect centers responsible for the blue band optical absorption are assigned to ionized Zni and V+O. SEM images illustrated that H+ implantation diluted the ZnAl2O4 second phase, which reaccumulated after O2 annealing.