Local structures of free-standing Al{sub x}Ga{sub 1-x}N thin films studied by extended x-ray absorption fine structure
- Center for Advanced Materials, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
- Department of Electronic Materials Engineering, Research School of Physical Sciences and Engineering, Australian National University, Canberra, (Australia)
- Department of Materials Science and Mineral Engineering, University of California, Berkeley, California 94720 (United States)
- Honeywell Technology Center, Plymouth, Minnesota 55420 (United States)
Local structural information for the first two atomic shells surrounding Ga atoms in free standing Al{sub x}Ga{sub 1-x}N alloy films has been obtained by extended x-ray absorption fine structure spectroscopy. For an AlN mole fraction ranging from 0 to 0.6, we found that the first shell Ga-N bond length had only a weak composition dependence, roughly one quarter of that predicted by Vegard's Law. In the second shell, the Ga-Ga bond length was significantly longer than that of Ga-Al ({delta}{approx}0.04-0.065 Aa). A bond-type specific composition dependence was observed for the second shell cation-cation distances. While the composition dependence of the Ga-Ga bond length is {approx}70% of that predicted by Vegard's Law, the Ga-Al bond length was essentially composition independent. These results suggested that local strain in Al{sub x}Ga{sub 1-x}N was also accommodated by lattice distortion in the Al cation sublattice. (c) 1999 American Institute of Physics.
- OSTI ID:
- 20217757
- Journal Information:
- Applied Physics Letters, Vol. 75, Issue 26; Other Information: PBD: 27 Dec 1999; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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