Current density impact on the emission behavior of GaN‐based blue emitting LEDs in the temperature range of 4.2–400 K

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE(2014)

Cited 2|Views2
No score
Abstract
Blue emitting GaN-based light emitting diodes (LEDs) show a distinct spectral behavior with respect to temperature and injection current density. Operating LEDs with short current pulses of 500 ns provides a steady state situation, which allows investigating the emission behavior of LEDs at a certain device temperature thereby maintaining thermal equilibrium. The LEDs were examined in a temperature range between 4.2 and 400 K and in a current density range between 2 and 50 A cm(-2). Low temperature investigations showed a blue shift of the electroluminescence spectra (EL) with respect to junction temperature, which is assigned to the radiative recombination of localized excitons. In the elevated temperature region a distinct red shift due to energy gap shrinkage was observed. Further we expect an exciton lifetime reduction at 4.2 K. Additionally, the influence of the driving parameters (pulse injection current or direct current (DC)) in the presence of piezoelectric fields is discussed and separated into band filling effect and occurrence of fields, which screen the quantum confined Stark effect. Low temperature investigations indicate that band filling is mainly responsible for the blue shift of the EL spectra with respect to the injection current. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
More
Translated text
Key words
current density,junction temperature,GaN,light-emitting diodes
AI Read Science
Must-Reading Tree
Example
Generate MRT to find the research sequence of this paper
Chat Paper
Summary is being generated by the instructions you defined