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Title: Low-energy electro- and photo-emission spectroscopy of GaN materials and devices

In hot-electron semiconductor devices, carrier transport extends over a wide range of conduction states, which often includes multiple satellite valleys. Electrical measurements can hardly give access to the transport processes over such a wide range without resorting to models and simulations. An alternative experimental approach however exists which is based on low-energy electron spectroscopy and provides, in a number of cases, very direct and selective information on hot-electron transport mechanisms. Recent results obtained in GaN crystals and devices by electron emission spectroscopy are discussed. Using near-band-gap photoemission, the energy position of the first satellite valley in wurtzite GaN is directly determined. By electro-emission spectroscopy, we show that the measurement of the electron spectrum emitted from a GaN p-n junction and InGaN/GaN light-emitting diodes (LEDs) under electrical injection of carriers provides a direct observation of transport processes in these devices. In particular, at high injected current density, high-energy features appear in the electro-emission spectrum of the LEDs showing that Auger electrons are being generated in the active region. These measurements allow us identifying the microscopic mechanism responsible for droop which represents a major hurdle for widespread adoption of solid-state lighting.
Authors:
;  [1] ;  [2] ; ; ;  [3] ; ;  [1] ;  [4]
  1. Laboratoire de Physique de la Matière Condensée, CNRS-Ecole Polytechnique, 91128 Palaiseau Cedex (France)
  2. (United States)
  3. Materials Department, University of California, Santa Barbara, California 93106 (United States)
  4. Seoul Viosys Co. Ltd., 1-36 727, Won-Si Dong, Danwon-Gu, Ansan City, Kyunggi-do 425-851 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22399292
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 11; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPUTERIZED SIMULATION; CRYSTALS; CUBIC LATTICES; CURRENT DENSITY; ELECTRON EMISSION; ELECTRON SPECTRA; ELECTRON SPECTROSCOPY; ELECTRONS; EMISSION SPECTRA; EMISSION SPECTROSCOPY; GALLIUM NITRIDES; INDIUM COMPOUNDS; LIGHT EMITTING DIODES; PHOTOEMISSION; P-N JUNCTIONS