Dislocation related droop in InGaN/GaN light emitting diodes investigated via cathodoluminescence

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Abstract

Today's energy saving solutions for general illumination rely on efficient white light emitting diodes (LEDs). However, the output efficiency droop experienced in InGaN based LEDs with increasing current injection is a serious limitation factor for future development of bright white LEDs. We show using cathodoluminescence (CL) spatial mapping at different electron beam currents that threading dislocations are active as nonradiative recombination centers only at high injection conditions. At low current, the dislocations are inactive in carrier recombination due to local potentials, but these potentials are screened by carriers at higher injection levels. In CL images, this corresponds to the increase of the dark contrast around dislocations with the injection (excitation) density and can be linked with droop related to the threading dislocations. Our data indicate that reduction of droop in the future efficient white LED can be achieved via a drastic reduction of the dislocation density by using, for example, bulk native substrates.

Detaljer

Författare
Enheter & grupper
Externa organisationer
  • Linköping University
  • Glo AB
  • Tokyo University of Agriculture and Technology
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Den kondenserade materiens fysik
Originalspråkengelska
Artikelnummer251106
TidskriftApplied Physics Letters
Volym107
Utgåva nummer25
StatusPublished - 2015 dec 21
PublikationskategoriForskning
Peer review utfördJa