Regulation of oxygen vacancies in nitrogen-doped Ga₂O₃ films for high-performance MSM solar-blind UV photodetectors

Gallium oxide (Ga2O3)-based solar-blind photodetectors (SBPDs) have shown promising applications. However, the concentration of native oxygen vacancies (V-O) impacts the photoelectrical performance of Ga2O3 films. Herein, a nitrogen-doping method is proposed to decrease the concentration of V-O in Ga2O3 films. Specifically, Ga2O3 thin films were grown by radio frequency magnetron sputtering using nitrogen-containing ceramic targets at different substrate temperatures ranging from room temperature to 800 degrees C. Furthermore, their structural, optical and electrical properties were systematically investigated. Since the concentration of V-O in Ga2O3 films is largely lowered through introduction of nitrogen species at V-O sites, the persistent photoconductivity effect is significantly restrained. As a result, N-doped Ga2O3 photodetectors exhibit large photo-to-dark current ratios (PDCRs) of 4.6 x 10(6), a high responsivity of 0.27 A W-1, a large external quantum efficiency of 132.5%, and a high specific detectivity of 6.6 x 10(11) Jones at 900 mu W cm(-2) light intensities at 5 V. Moreover, the PDCRs and detectivity of a N-doped device are increased by 2.2 x 10(3) and 50.6 times, respectively, as compared to those of the undoped device. These results demonstrate that the regulation of V-O by nitrogen-doping can effectively improve the photoelectric performance of the device, opening up new opportunities for fabricating high-performance SBPDs.