Variation of GaN valence bands with biaxial stress: Quantification of residual stress and impact on fundamental band parameters
- North Carolina State Univ., Raleigh, NC (United States); and others
The authors provide the widest estimate thus far of the range of tensile and compressive stress ({minus}3.8 to 3.5 kbar) that GaN epitaxial material can withstand before relaxation occurs, and an unambiguous determination of the spin-orbit splitting {Delta}{sub SO} = 17.0 {+-} 1 meV for the material. These are achieved by analyzing 10K reflectance data for the energy separation of transitions between the uppermost valence bands and the lowest conduction band of wurtzitic GaN as a function of biaxial stress for a series of GaN films grown on both Al{sub 2}O{sub 3} and 6H-SiC substrates. The data explicitly show the nonlinear behavior of the excitonic energy splittings B-A and C-A vs. the energy position of the A exciton, which stands in contrast to the linear approximations used by previous workers analyzing material grown only on Al{sub 2}O{sub 3} substrates. Further, the lineshape ambiguities present in GaN reflectance spectra that hindered the accurate determination of such excitonic energies have also been resolved by analyzing these data in reciprocal space, where critical point energies are determined by phase effects to an accuracy of {+-}0.5 meV.
- Sponsoring Organization:
- Office of Naval Research, Washington, DC (United States)
- OSTI ID:
- 585818
- Report Number(s):
- CONF-961202-; ISBN 1-55899-353-3; TRN: IM9810%%48
- Resource Relation:
- Conference: 1996 Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 2-6 Dec 1996; Other Information: PBD: 1997; Related Information: Is Part Of III-V nitrides; Ponce, F.A. [ed.] [Xerox Palo Alto Research Center, CA (United States)]; Moustakas, T.D. [ed.] [Boston Univ., MA (United States)]; Akasaki, I. [ed.] [Meijo Univ., Nagoya (Japan)]; Monemar, B.A. [ed.] [Linkoeping Univ. (Sweden)]; PB: 1278 p.; Materials Research Society symposium proceedings, Volume 449
- Country of Publication:
- United States
- Language:
- English
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