Demonstration of high wall-plug efficiency III-nitride micro-light-emitting diodes with MOCVD-grown tunnel junction contacts using chemical treatments
Matthew S. Wong, Joonho Back, David Hwang, Changmin Lee, Jianfeng Wang, Srinivas Gandrothula, Tal Margalith, James S. Speck, Shuji Nakamura, Steven P. DenBaars
Abstract
High wall-plug efficiency (WPE) micro-light-emitting diodes with metalorganic chemical vapor deposition-grown tunnel junction (TJ) contacts are demonstrated. By employing chemical treatments before sidewall activation, the 20 × 20 μm2 TJ devices resulted in a voltage penalty of 0.2 V at 20 A cm−2, compared to devices with indium-tin oxide (ITO) contacts. Moreover, the enhancement in light output power was more than 40% higher than ITO devices. Hence, the TJ devices yielded the peak external quantum efficiency (EQE) and WPE of 56% and 55%, respectively, indicating the improvements of 64% and 77% in peak EQE and WPE compared to ITO devices.