Efficient defect control of zinc vacancy in undoped ZnO microtubes for optoelectronic applications

摘要

Here, we report a strategy to regulate the defect level of zinc vacancy (V-Zn) in acceptor-rich ZnO (A-ZnO) microtubes by optical vapor supersaturated precipitation (OVSP) combined with the first-principles calculation. The formation energy (FE) of V-Zn in ZnO is calculated based on the density functional theory, indicating the FE of V-Zn depending upon the surrounding Zn chemical potential in ZnO. The defect level of V-Zn is experimentally controlled in the A-ZnO microtubes by regulating the concentration of oxygen during the OVSP process. For the high oxygen concentration, the photoluminescence intensity of V-Zn-related donor-acceptor pair emission is enhanced by 46, compared with those grown in oxygen-deficient conditions. Meanwhile, a defective 2LA mode appeared in the Raman spectra of A-ZnO microtubes with the increase in oxygen concentration, confirming the controllability of the generation of V-Zn. The V-Zn defects induce the conductive filaments for the resistive switching behavior in the A-ZnO microtubes, by which the on/off ratio can be enhanced by up to similar to 10(3). Moreover, the tunable current-induced thermal tunneling electroluminescence was also realized by the defect-controlled A-ZnO microrods/tubes. This work opens new opportunities for the design of novel optoelectronic devices by defect-engineered wide-bandgap semiconductors in future. Published under an exclusive license by AIP Publishing.