Enhancement of crystalline quality and solar-blind photodetection characteristics of ε-Ga2O3 films by introducing Zn impurity

Abstract

ε-Ga₂O₃ films with and without Zn impurity were epitaxially grown by metal organic chemical vapor deposition on a c-plane sapphire substrate, and were then face-to-face annealed in an oxygen atmosphere at 600 °C. The structural and photoelectric properties of the thin films were characterized and analyzed in detail. The Zn-doped ε-Ga₂O₃ photodetector exhibits an ultra-high specific detectivity of 1.7 × 10¹⁶ Jones, a very quick response speed of less than 40 ms, and an extremely high UV-visible rejection ratio of 2.0 × 10⁸ at a 10 V bias. In addition, the temperature dependent photoresponse properties have been investigated from 30 °C to 190 °C. The compensation effect of Zn impurities and their suppression of oxygen vacancies, as well as the improvement of crystal quality, should be responsible for the excellent performance of the device. Our results provide a new idea and guidance for achieving high-performance solar-blind photodetectors based on Ga₂O₃.