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Title: A physical model for the reverse leakage current in (In,Ga)N/GaN light-emitting diodes based on nanowires

We investigated the origin of the high reverse leakage current in light emitting diodes (LEDs) based on (In,Ga)N/GaN nanowire (NW) ensembles grown by molecular beam epitaxy on Si substrates. To this end, capacitance deep level transient spectroscopy (DLTS) and temperature-dependent current-voltage (I-V) measurements were performed on a fully processed NW-LED. The DLTS measurements reveal the presence of two distinct electron traps with high concentrations in the depletion region of the p-i-n junction. These band gap states are located at energies of 570 ± 20 and 840 ± 30 meV below the conduction band minimum. The physical origin of these deep level states is discussed. The temperature-dependent I-V characteristics, acquired between 83 and 403 K, show that different conduction mechanisms cause the observed leakage current. On the basis of all these results, we developed a quantitative physical model for charge transport in the reverse bias regime. By taking into account the mutual interaction of variable range hopping and electron emission from Coulombic trap states, with the latter being described by phonon-assisted tunnelling and the Poole-Frenkel effect, we can model the experimental I-V curves in the entire range of temperatures with a consistent set of parameters. Our model should be applicable to planar GaN-based LEDs as well. Furthermore,more » possible approaches to decrease the leakage current in NW-LEDs are proposed.« less
Authors:
; ; ; ;  [1] ; ; ; ;  [2]
  1. Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5–7, D-10117 Berlin (Germany)
  2. Department of Information Engineering, University of Padova, Via Gradenigo 6/B, 35131 Padova (Italy)
Publication Date:
OSTI Identifier:
22494946
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 4; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CAPACITANCE; DEEP LEVEL TRANSIENT SPECTROSCOPY; ELECTRIC CONDUCTIVITY; GALLIUM NITRIDES; LEAKAGE CURRENT; LIGHT EMITTING DIODES; MOLECULAR BEAM EPITAXY; NANOWIRES; TEMPERATURE DEPENDENCE