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Elimination of resistive losses in large-area LEDs by new diffusion-driven devices

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Kivisaari, Pyry
dc.contributor.author Kim, Iurii
dc.contributor.author Suihkonen, Sami
dc.contributor.author Oksanen, Jani
dc.date.accessioned 2017-05-25T09:01:51Z
dc.date.available 2017-05-25T09:01:51Z
dc.date.issued 2017
dc.identifier.citation Kivisaari, Pyry & Kim, Iurii & Suihkonen, Sami & Oksanen, Jani. 2017. Elimination of resistive losses in large-area LEDs by new diffusion-driven devices. Proceedings of SPIE. Volume 10124. 7. DOI: 10.1117/12.2251108. en
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/26281
dc.description.abstract High-power operation of conventional GaN-based light-emitting diodes (LEDs) is severely limited by current crowding, which increases the bias voltage of the LED, concentrates light emission close to the p-type contact edge, and aggravates the efficiency droop. Fabricating LEDs on thick n-GaN substrates alleviates current crowding but requires the use of expensive bulk GaN substrates and fairly large n-contacts, which take away a large part of the active region (AR). In this work, we demonstrate through comparative simulations how the recently introduced diffusion-driven charge transport (DDCT) concept can be used to realize lateral heterojunction (LHJ) structures, which eliminate most of the lateral current crowding. Specifically in this work, we analyze how using a single-side graded AR can both facilitate electron and hole diffusion in DDCT and increase the effective AR thickness. Our simulations show that the increased effective AR thickness allows a substantial reduction in the efficiency droop at large currents, and that unlike conventional 2D LEDs, the LHJ structure shows practically no added efficiency loss or differential resistance due to current crowding. Furthermore, as both electrons and holes enter the AR from the same side without any notable potential barriers in the LHJ structure, the LHJ structure shows an additional wall-plug efficiency gain over the conventional structures under comparison. This injection from the same side is expected to be even more interesting in multiple quantum well structures, where carriers typically need to surpass several potential barriers in conventional LEDs before recombining. In addition to simulations, we also demonstrate selective-area growth of a finger structure suitable for operation as an LHJ device with 2µm distance between n- and p-GaN regions. fi
dc.format.extent 7
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher SPIE en
dc.relation info:eu-repo/grantAgreement/EC/H2020/638173/EU//iTPX fi
dc.relation.ispartofseries Proceedings of SPIE fi
dc.relation.ispartofseries Volume 10124 fi
dc.rights © 2017 SPIE. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. en
dc.subject.other Electrical engineering en
dc.subject.other Materials science en
dc.subject.other Physics en
dc.title Elimination of resistive losses in large-area LEDs by new diffusion-driven devices en
dc.type A4 Artikkeli konferenssijulkaisussa fi
dc.description.version Peer reviewed en
dc.rights.holder SPIE
dc.contributor.school Perustieteiden korkeakoulu fi
dc.contributor.school School of Science en
dc.contributor.department Neurotieteen ja lääketieteellisen tekniikan laitos fi
dc.contributor.department Department of Neuroscience and Biomedical Engineering en
dc.subject.keyword resistive losses en
dc.subject.keyword lateral current spreading en
dc.subject.keyword light emitting diode en
dc.identifier.urn URN:NBN:fi:aalto-201705154741
dc.type.dcmitype text en
dc.identifier.doi 10.1117/12.2251108
dc.type.version Post print en

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