Efficiency droop due to electron spill-over and limited hole injection in III-nitride visible light-emitting diodes employing lattice-matched InAlN electron blocking layers

Suk Choi, Mi Hee Ji, Jeomoh Kim, Hee Jin Kim, Md M. Satter, P. D. Yoder, Jae Hyun Ryou, Russell D. Dupuis, Alec M. Fischer, Fernando Ponce

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76 Scopus citations

Abstract

Data and analysis are presented for the study of efficiency droop in visible III-nitride light-emitting diodes (LEDs) considering the effects of both electron spill-over out of active region and hole injection into the active region. Performance characteristics of blue LEDs with lattice-matched In 0.18Al 0.82N electron-blocking layers (EBLs) with different thicknesses were measured in order to exclude the effects of strain and doping efficiency of the EBL, and the quantum efficiencies were analyzed taking account of the electron spill-over current and the relative hole concentration. The results suggest that the highest efficiency in LEDs with a 15-nm In 0.18Al 0.82N EBL is due to relatively lower hole-blocking effect, hence higher hole injection than in LEDs with a 20-nm EBL, while providing a higher potential barrier for reduced electron spill-over than in LEDs with thinner EBLs. This study suggests that the EBL hole-blocking and electron-confinement effects should be considered in order to achieve higher light output power and reduced efficiency droop at high currents.

Original languageEnglish (US)
Article number161110
JournalApplied Physics Letters
Volume101
Issue number16
DOIs
StatePublished - Oct 15 2012

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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