Thermal-Assisted UV-Photon Irradiation to Improve Crystallization and Luminescence Efficiency of ZnO

Defect manipulation plays an important role in regulating luminescence efficiency and electric performance of wide bandgap semiconductor devices. ZnO possesses complex defects, resulting in a bottleneck for p-type doping due to self-compensation. In this article, we propose a strategy to manipulate the defects in ZnO microwires (MWs) via thermal-assisted UV-photon irradiation. With this strategy, the photoluminescence (PL) and electroluminescence (EL) of the near band edge emission are enhanced. The improvement in radiation efficiency is attributed to the recrystallization of the ZnO MWs, by which the oxygen vacancy and zinc interstitial defects are suppressed. The combination of UV photo-chemical and thermal quenching for defect regulation is confirmed, for the first time, by PL and EL spectra. The work provides insights into defect engineering for luminescence efficiency improvement in wide bandgap semiconductor devices.