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Title: Increase in the Shockley–Read–Hall recombination rate in InGaN/GaN QWs as the main mechanism of the efficiency droop in LEDs at high injection levels

It is shown that the efficiency droop observed as the current through a GaN-based light-emitting diode increases is due to a decrease in the Shockley–Read–Hall nonradiative lifetime. The lifetime decreases with increasing current because a steadily growing number of traps in the density-of-states tails of InGaN/GaN quantum wells become nonradiative recombination centers upon the approach of quasi-Fermi levels to the band edges. This follows from the correlation between the efficiency droop and the appearance of negative differential capacitance, observed in the study. The correlation appears due to slow trap recharging via the trap-assisted tunneling of electrons through the n-type barrier of the quantum well and to the inductive nature of the diode-current variation with forward bias.
Authors:
; ;  [1]
  1. Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)
Publication Date:
OSTI Identifier:
22469668
Resource Type:
Journal Article
Resource Relation:
Journal Name: Semiconductors; Journal Volume: 49; Journal Issue: 12; Other Information: Copyright (c) 2015 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; CAPACITANCE; CORRELATIONS; DENSITY OF STATES; DIFFUSION BARRIERS; ELECTRONS; FERMI LEVEL; GALLIUM NITRIDES; HALL EFFECT; INDIUM COMPOUNDS; LIFETIME; LIGHT EMITTING DIODES; N-TYPE CONDUCTORS; QUANTUM WELLS; RECOMBINATION; TRAPS; TUNNEL EFFECT