title: Controlling electron overflow in phosphor-free InGaN/GaN nanowire white light-emitting diodes.
abstract: We have investigated for the first time the impact of electron overflow on the performance of nanowire light-emitting diodes (LEDs) operating in the entire visible spectral range, wherein intrinsic white light emission is achieved from self-organized InGaN quantum dots embedded in defect-free GaN nanowires on a single chip. Through detailed temperature-dependent electroluminescence and simulation studies, it is revealed that electron leakage out of the device active region is primarily responsible for efficiency degradation in such nanowire devices, which in conjunction with the presence of nonradiative surface recombination largely determines the unique emission characteristics of nanowire light-emitting diodes. We have further demonstrated that electron overflow in nanowire LEDs can be effectively prevented with the incorporation of a p-doped AlGaN electron blocking layer, leading to the achievement of phosphor-free white light-emitting diodes that can exhibit for the first time virtually zero efficiency droop for injection currents up to ~2200 A/cm(2). This study also provides unambiguous evidence that Auger recombination is not the primary mechanism responsible for efficiency droop in GaN-based nanowire light-emitting diodes.
authors.affiliation: Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec H3A 2A7, Canada.
authors.forename: Hieu Pham Trung
authors.initials: HP
authors.lastname: Nguyen
authors.forename: Kai
authors.initials: K
authors.lastname: Cui
authors.forename: Shaofei
authors.initials: S
authors.lastname: Zhang
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Djavid
authors.forename: Andreas
authors.initials: A
authors.lastname: Korinek
authors.forename: Gianluigi A
authors.initials: GA
authors.lastname: Botton
authors.forename: Zetian
authors.initials: Z
authors.lastname: Mi
mesh_terms: D003116:Color; D004579:Electron Transport; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry*; D007204:Indium / Q000737:chemistry*; D008029:Lighting / Q000295:instrumentation*; D008422:Materials Testing; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D012666:Semiconductors
chemical_list: D007204:Indium; C473348:gallium nitride; D005708:Gallium; C513701:indium nitride