Study on Bidirectional Ultraviolet Light-Emitting Diodes Based on the Au/i-AlN/p-GaN MIS Heterojunction

Abstract

Aluminum nitride (AlN) thin films are widely used in optoelectronic devices. Ultraviolet (UV) and violet light-emitting diodes (LEDs) of the Au/i-AlN/p-GaN metal–insulator-semiconductor (MIS) structure were prepared by magnetron sputtering, which can achieve bidirectional luminescence. The result of I–V tests at variable temperatures indicated that the device exhibits highly stable rectification characteristics at different ambient temperatures. Under a driving current (0.02 mA), purple light was detected under forward bias and reverse bias. With the increase of driving current (1–2.5 mA), strong purple light was emitted under forward bias, and strong ultraviolet light emission was detected under reverse bias. In addition, considering the influence of temperature on the luminescence intensity, the electroluminescence (EL) test was carried out under the condition of variable temperature in both forward and reverse cases. Finally, the EL mechanism of the device was analyzed by Gaussian peak fitting of the spectrum and energy band structure. The research of bidirectional ultraviolet and violet LEDs based on the Au/i-AlN/p-GaN MIS structure provides an effective method for designing and developing a simple structure UV-LED.