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

Journal Article · Sat Mar 21 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4913928· OSTI ID:22399292

Piccardo, Marco; Weisbuch, Claude ^[1]; Iveland, Justin; Nakamura, Shuji; Speck, James S. ^[2]; Martinelli, Lucio; Peretti, Jacques ^[1]; Choi, Joo Won ^[3]

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1. Laboratoire de Physique de la Matière Condensée, CNRS-Ecole Polytechnique, 91128 Palaiseau Cedex (France)
2. Materials Department, University of California, Santa Barbara, California 93106 (United States)
3. Seoul Viosys Co. Ltd., 1-36 727, Won-Si Dong, Danwon-Gu, Ansan City, Kyunggi-do 425-851 (Korea, Republic of)

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.

• OSTI ID: 22399292
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 11; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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