The size and temperature effect of ideality factor in GaN/InGaN multiple quantum wells micro‐light‐emitting diodes

Abstract In this paper, the GaN/InGaN multiple quantum wells (MQWs) micro‐light‐emitting diode (micro‐LED) devices of different size with green light emission were fabricated. The ideality factor of micro‐LED was discussed. For temperature‐dependent electrical characterization, the current–voltage relationship within a temperature category of 303–573 K was measured. The contact resistance between electrodes and GaN was exhibited, and a favorable ohmic contact was achieved for p ‐electrode and p ‐GaN. Next, the temperature and size effect of ideality factor was demonstrated. All size devices showed an extremely low factor smaller than 1.9. In order to better evaluate the temperature dependence, the thermal characterization was performed with a constant current and voltage mode. The 80‐μm device revealed a satisfactory temperature coefficient, namely, 1.92 mV/K at the forward voltage and 2.66 kA·K at the reverse bias. For temperature‐dependent optical characterization, the irradiance and brightness from 303 to 453 K of 100 μm were demonstrated. Even at 453 K, the brightness is still favorable as 34,520 nits. Following this, the luminous efficiency droop with increasing injection current density was described and discussed.