It is believed that low power conversion efficiency in commercial MQW LEDs occurs as a result of efficiency droop, current-induced dynamic degradation of the internal quantum efficiency, injection efficiency, and extraction efficiency. Broadly speaking, all these “quenching” mechanisms could be referred to as the optical losses. The vast advances of high-power InGaN and AlGaInP MQW LEDs have been achieved by addressing these losses. In contrast to these studies, in this paper we consider an alternative approach to make high-power LEDs more efficient. We identify current-induced electrical efficiency degradation (EED) as a strong limiting factor of power conversion efficiency. We found that EED is caused by current crowding followed by an increase in current-induced series resistance of a device. By decreasing the current spreading length, EED also causes the optical efficiency to degrade and stands for an important aspect of LED performance. This paper gives scientists the opportunity to look for different attributes of EED.

Date Published: 27 February 2014
PDF: 9 pages
Proc. SPIE 9003, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XVIII, 90031T (27 February 2014); doi: 10.1117/12.2041567

Published in SPIE Proceedings Vol. 9003:
Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XVIII
Klaus P. Streubel; Heonsu Jeon; Li-Wei Tu; Martin Strassburg, Editor(s)