Ultra-violet and yellow-green emissions under intriguing bidirectional DC driving based on Au/i-GaO/n-GaN MIS heterojunction light-emitting diodes

GaN-based light-emitting diodes (LEDs) have attracted widespread attention owing to their advantages of high efficiency and brightness, stable emission and full color emission. However, only a few studies have reported LEDs with bidirectional driving. Herein, we first fabricated an Au/i-Ga 2 O 3 /n-GaN heterojunction LED with a striking electrical performance of bidirectional DC driving. The results of I - V tests indicated that the LED possesses excellent rectification characteristics. The LED exhibited an extremely low leakage current of 1.6 × 10 −11 A at ambient temperature, which increased to 4.3 × 10 −9 A at 100 °C. In addition, electroluminescence (EL) analysis further confirmed the robust thermal stability of this heterojunction LED. It is noteworthy that the Au/i-Ga 2 O 3 /n-GaN heterojunction LED contains bidirectional DC driving. When the forward current is injected, this LED exhibits the strongest ultraviolet emission (376 nm) at 90 mA, and the peak position of EL spectra remains consistent with the temperature ranging from 50 to 90 °C. When reverse current is injected, the LED mainly emitted mixed yellow-green light, and the color coordinate changed from (0.336, 0.363) to (0.303, 0.350). With the increase in external temperature to 80 °C, the EL intensity reached as high as 95% of that at ambient temperature. This finding not only adds a feasible strategy to fabricate GaN-based diodes with intriguing bidirectional DC driving but also opens up a way for the development of special lighting semiconductor devices. The low lattice mismatch between β-Ga 2 O 3 and GaN alleviates interface defects and improves device performance, and the EL spectra of Ga 2 O 3 /GaN heterojunction devices emit ultra-violet and yellow-green light at forward and reverse bias.