270nm pseudomorphic ultraviolet light-emitting diodes with over 60mW continuous wave output power

Abstract

In this letter, the achievement of over 60mW output power from pseudomorphic ultraviolet light-emitting diodes in continuous wave operation is reported. Die thinning and encapsulation improved the photon extraction efficiency to over 15%. Improved thermal management and a high characteristic temperature resulted in a low thermal rolloff up to 300mA injection current with an output power of 67mW, an external quantum efficiency (EQE) of 4.9%, and a wall plug efficiency (WPE) of 2.5% for a single-chip device emitting at 271nm in continuous wave operation. © 2013 The Japan Society of Applied Physics.