Electrical and structural properties of AlN/GaN and AlGaN/GaN heterojunctions
- Institute of Rare Metals, Moscow, 119017, B. Tolmachevsky, 5 (Russian Federation)
- SVT Associates, Incorporated, 7620 Executive Drive, Eden Prairie, Minnesota 55344 (United States)
- Department of Materials Science and Engineering, University of Florida, P.O. Box 116400, Gainesville, Florida 32611 (United States)
- Department of Semiconductor Materials Science, Moscow Institute of Steel and Alloys, Moscow, Leninsky Avenue 4 (Russian Federation)
The electrical and structural properties of AlN/GaN heterostructures grown by molecular beam epitaxy on sapphire are compared with those of AlGaN/GaN heterostructures. The structural characteristics as assessed by x-ray diffraction show little difference but the electron density in the two-dimensional electron gas is about twice higher for AlN/GaN structures with only slightly lower mobility than in AlGaN/GaN. By proper choice of the Fe doping in GaN(Fe) and the thickness of unintentionally doped GaN layers, the composite buffer of the structure can be made semi-insulating. The current through the AlN/GaN structures is determined by tunneling through the AlN barrier and is much higher than that for AlGaN/GaN films due to the lower thickness of AlN compared to AlGaN. Increasing the thickness of AlN from 3 to 4 nm decreases the leakage current by about an order of magnitude.
- OSTI ID:
- 21182602
- Journal Information:
- Journal of Applied Physics, Vol. 104, Issue 5; Other Information: DOI: 10.1063/1.2973463; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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