Photonics Research, 2017, 5 (2): 02000A44, Published Online: Oct. 10, 2018
Recombination mechanisms and thermal droop in AlGaN-based UV-B LEDs Download: 936次
Abstract
This paper reports a comprehensive analysis of the origin of the electroluminescence (EL) peaks and of the thermal droop in UV-B AlGaN-based LEDs. By carrying out spectral measurements at several temperatures and currents, (i) we extract information on the physical origin of the various spectral bands, and (ii) we develop a novel closed-form model based on the Shockley–Read–Hall theory and on the ABC rate equation that is able to reproduce the experimental data on thermal droop caused by non-radiative recombination through deep levels. In the samples under test, the three EL bands are ascribed to the following processes: band-to-band recombination in the quantum wells (main EL peak), a parasitic intra-bandgap radiative transition in the quantum well barriers, and a second defect-related radiative process in the p -AlGaN superlattice.
Carlo De Santi, Matteo Meneghini, Desiree Monti, Johannes Glaab, Martin Guttmann, Jens Rass, Sven Einfeldt, Frank Mehnke, Johannes Enslin, Tim Wernicke, Michael Kneissl, Gaudenzio Meneghesso, Enrico Zanoni. Recombination mechanisms and thermal droop in AlGaN-based UV-B LEDs[J]. Photonics Research, 2017, 5(2): 02000A44.