Low-energy electro- and photo-emission spectroscopy of GaN materials and devices
- CNRS-Ecole Polytechnique, Palaiseau (France); Univ. of California, Santa Barbara, CA (United States)
- Univ. of California, Santa Barbara, CA (United States)
- CNRS-Ecole Polytechnique, Palaiseau (France)
- Seoul Viosys Co. Ltd., Won-Si Dong, Danwon-Gu, Ansan City (Korea)
We report that 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. Finally, these measurements allow us identifying the microscopic mechanism responsible for droop which represents a major hurdle for widespread adoption of solid-state lighting.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Energy Efficient Materials (CEEM)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0001009
- OSTI ID:
- 1369764
- Journal Information:
- Journal of Applied Physics, Vol. 117, Issue 11; Related Information: CEEM partners with the University of California, Santa Barbara (lead); Purdue University; Los Alamos National Laboratory; National Renewable Energy Laboratory; ISSN 0021-8979
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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