AlGaN multiple quantum well based deep UV LEDs and their applications



In this paper we will describe the approaches that we have used to grow AlGaN-based multiple quantum well deep UV LED structures and to overcome issues of doping efficiency, cracking, and slow growth rates both for the n- and the p-type layers of the device structures. This has led to the fabrication of devices with emission from 250–340 nm and cw-milliwatt powers at pump currents of only 20 mA (Vf ≤ 6 V). Record wall plug efficiencies as high as 1.5% are now achievable for devices with emission at 280 nm. Thermal management and a proper device design are not only a key to achieving these record performance numbers but are also crucial to device reliability. We will also discuss some of our initial research to clarify the factors influencing the lifetime of the deep UV LEDs. In addition to our own work, we will review the results from the excellent research carried out at several other laboratories worldwide. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)