Investigation of the temperature dependent efficiency droop in UV LEDs
Semicond. Sci. Technol., vol. 28, no. 125021 (2013).
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The influence of the dislocation density and the carrier-confining potentials on the temperature dependent behavior of the external quantum efficiency (EQE) of near-ultraviolet light-emitting diodes (LEDs) at different current densities has been investigated. The LED efficiencies were found to be very temperature sensitive with characteristic temperatures ranging from 48 to 207 K. In the low current density region the temperature dependence of the EQE is mainly dominated by the Shockley-Read-Hall recombination and hence the dislocation density of the device. In the high current density region, carrier leakage from the quantum wells is the main factor influencing the decrease in the EQE with ambient temperature, and in this region the LEDs become less temperature sensitive with increasing quantum well barrier height.
1 Technical University of Berlin, Institute of Solid-State Physics, D-10623 Berlin, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany
85.60.Jb Light-emitting devices; 85.60.Bt Optoelectronic device characterization, design, and modeling; 68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.; 73.63.Hs Quantum wells.