High-Temperature Analysis of GaN-Based Blue-LEDs for Future Power Electronic Applications

Commercial gallium-nitride-based blue-light-emitting diodes (LEDs), primarily fabricated for lighting applications, are evaluated at high temperatures (up to 700 K) for possible integration as an optocoupler emitter in high-density power electronic modules. The temperature- and injection-current-dependent internal quantum efficiencies (IQEs) and current-voltage characteristics of the blue-LEDs are studied. The IQE is extracted from the measured integrated electroluminescence (EL) intensity at different temperatures using the ABC model. The presented method helps evaluate the optimized injection current density to achieve minimum deviation in LED IQE at a broader range of operating temperatures. As per the ABC model, the LED can operate at 700 K with an IQE of 58.50% when it operates at a current density of 2 A/cm². The results show that for a temperature range of 77-700 K, the minimum deviation of IQE occurs when the injected current density is between 1 to 10 A/cm². Normalized external quantum efficiency (EQE) of the device at different temperatures was also extracted using the ABC model.