Status of high efficiency and high power ThinGaN®-LED development

Abstract

In this paper we report on the improvement of ThinGaN®-PowerLED structures in epitaxy, chip design, phosphor efficiency and package design. The brightness of these devices increased by a factor of 4 over the last 4 years. We demonstrate 604 mW blue (440 nm; 3,24 V; 53% WPE), 129 lm cool-white light (5000 K; 3,25 V, 113 lm/W) and 88.2 lm warm-white (3200 K; 74.4 lm/W; CRI 80) emission for 1mm2-chip Dragon power LEDs at 350 mA operation. In an advanced device we realized values of 643 mW blue (440 nm; 3,24 V; 350 mA; WPE: 57%) and 155 lm white (5000 K, 350 mA, 3,24 V, 136 lm/W) emission. To our knowledge these are the highest brightness and efficacy values reported in literature. Also at 1.4 A operation current the performance of these multi quantum well epitaxy based structures is superior to the values reported for double heterostructure epitaxy based structures. By combination of phosphor converted white and red 1 mm2 chip LEDs we realized a 3000 K warm white emitting device with 100 lm/W, CRI 90 and 850 lm emission. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.