Dislocation related droop in InGaN/GaN light emitting diodes investigated via cathodoluminescence
2015 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 107, no 25, 251106- p.Article in journal (Refereed) PublishedText
Todays 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. (C) 2015 AIP Publishing LLC.
Place, publisher, year, edition, pages
AMER INST PHYSICS , 2015. Vol. 107, no 25, 251106- p.
Physical Sciences Chemical Sciences
IdentifiersURN: urn:nbn:se:liu:diva-125162DOI: 10.1063/1.4938208ISI: 000368442100006OAI: oai:DiVA.org:liu-125162DiVA: diva2:903397
Funding Agencies|Swedish Research Council (VR); Swedish Energy Agency2016-02-152016-02-152016-03-08