skip to main content

Title: Degradation of (InAlGa)N-based UV-B light emitting diodes stressed by current and temperature

The degradation of the electrical and optical properties of (InAlGa)N-based multiple quantum well light emitting diodes (LEDs) emitting near 308 nm under different stress conditions has been studied. LEDs with different emission areas were operated at room temperature and at constant current densities of 75 A/cm{sup 2}, 150 A/cm{sup 2}, and 225 A/cm{sup 2}. In addition, the heat sink temperature was varied between 15 °C and 80 °C. Two main modes for the reduction of the optical power were found, which dominate at different times of operation: (1) Within the first 100 h, a fast drop of the optical power is observed scaling exponentially with the temperature and having an activation energy of about 0.13 eV. The drop in optical power is accompanied by changes of the current-voltage (I-V) characteristic. (2) For operation times beyond 100 h, the optical power decreases slowly which can be reasonably described by a square root time dependence. Here, the degradation rate depends on the current density, rather than the current. Again, the rate of optical power reduction of the second mode depends exponentially on the temperature with an activation energy of about 0.21 eV. The drop in the optical power is accompanied by an increased reverse-bias leakage current.
Authors:
; ; ; ; ; ; ; ; ;  [1] ; ; ;  [2] ;  [1] ;  [3]
  1. Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany)
  2. Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, EW 6-1, 10623 Berlin (Germany)
  3. (Germany)
Publication Date:
OSTI Identifier:
22494834
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACTIVATION ENERGY; ALUMINIUM NITRIDES; CURRENT DENSITY; ELECTRIC CONDUCTIVITY; EV RANGE; HEAT SINKS; INDIUM NITRIDES; LEAKAGE CURRENT; LIGHT EMITTING DIODES; OPTICAL PROPERTIES; QUANTUM WELLS; STRESSES; TEMPERATURE RANGE 0273-0400 K; TIME DEPENDENCE