Junction temperature of 260 nm AlGaN UVC micro-LEDs under different irradiated Ta fluences

In this work, 260 nm UVC micro-LEDs with a size of 80 μm were fabricated and then were subject to two different fluences of heavy Ta ion irradiation. Junction temperatures of the fresh and irradiated micro-LEDs were tested by forward voltage method. At the ambient room temperature of 25.7℃, the fresh micro-LED and the irradiated micro-LEDs with fluences of 1×109 ions/cm2 and 5×109 ions/cm2 have junction temperatures of 53.4℃, 61.4℃ and 75.7℃ at a forward current of 25 mA, respectively. Degradation in I-V characteristics was observed with increasing the fluences of irradiation, thus generating higher junction temperature. The work helps to optimize thermal properties of UVC LEDs deployed in space scenarios.