Hybrid metal/GaO/GaN ultraviolet detector for obtaining low dark current and high responsivity.

In this work, we have proposed and fabricated a metal/GaO/GaN hybrid structure metal-semiconductor-metal ultraviolet photodetector with low dark current and high responsivity. The Schottky contact of Ni/GaO makes the GaO layer fully depleted. The strong electric field in the GaO depletion region can push the photo-induced electrons from the GaO layer into the GaN layer for more efficient carrier transport. Therefore, the hybrid structure simultaneously utilizes the advantage of the absorption to solar-blind ultraviolet light by the GaO layer and the high electron mobility of the GaN layer. Thus, the dark current and the photocurrent for the proposed device can be greatly improved. As a result, an extremely high photo-to-dark-current ratio of 1.46 × 10 can be achieved. Furthermore, quick rise and fall times of 0.213 s and 0.027 s at the applied bias of 6 V are also obtained, respectively.