skip to main content

Title: Variation of the external quantum efficiency with temperature and current density in red, blue, and deep ultraviolet light-emitting diodes

The temperature-dependent external quantum efficiencies (EQEs) were investigated for a 620 nm AlGaInP red light-emitting diodes (LEDs), a 450 nm GaInN blue LED, and a 285 nm AlGaN deep-ultraviolet (DUV) LED. We observed distinct differences in the variation of the EQE with temperature and current density for the three types of LEDs. Whereas the EQE of the AlGaInP red LED increases as temperature decreases below room temperature, the EQEs of GaInN blue and AlGaN DUV LEDs decrease for the same change in temperature in a low-current density regime. The free carrier concentration, as determined from the dopant ionization energy, shows a strong material-system-specific dependence, leading to different degrees of asymmetry in carrier concentration for the three types of LEDs. We attribute the EQE variation of the red, blue, and DUV LEDs to the different degrees of asymmetry in carrier concentration, which can be exacerbated at cryogenic temperatures. As for the EQE variation with temperature in a high-current density regime, the efficiency droop for the AlGaInP red and GaInN blue LEDs becomes more apparent as temperature decreases, due to the deterioration of the asymmetry in carrier concentration. However, the EQE of the AlGaN DUV LED initially decreases, then reaches an EQE minimum point, andmore » then increases again due to the field-ionization of acceptors by the Poole-Frenkel effect. The results elucidate that carrier transport phenomena allow for the understanding of the droop phenomenon across different material systems, temperatures, and current densities.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ; ; ; ;  [4]
  1. Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of)
  2. School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center, Chonbuk National University, Jeonju 54896 (Korea, Republic of)
  3. Department for Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
  4. LED Business, Samsung Electronics, Yongin 446-920 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22494877
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 2; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ASYMMETRY; CARRIERS; CURRENT DENSITY; IONIZATION; LIGHT EMITTING DIODES; QUANTUM EFFICIENCY; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; ULTRAVIOLET RADIATION