Growth and characterization of GaAs/AlAs superlattice alloys
The superlattice bandstructure of short-period GaAs/AlAs superlattices grown by molecular beam epitaxy resembles that of the AlGaAs alloy system. We have studied indirect gap GaAs/AlAs superlattice alloys using x-ray diffraction and pressure dependent magneto-luminescence. Analysis of the x-ray data shows that the AlAs layers are strained to be pseudomorphic with the GaAs substrate. Because the indirect conduction band ground state derives from the AlAs X-point these superlattice alloys must be treated as strained-layer superlattices. Interpretation of luminescence data using Kronig-Penney and tight-binding analyses of the superlattice bandstructure and optical dipole matrix elements shows that this experiment provides a sensitive measure of the conduction band offset for the GaAs/AlAs system. Quantum size effects lift the three-fold degeneracy of the X-point to yield an in-plane X band quantized according to the transverse electron mass (X/sub t/) and a separate X band along the superlattice axis quantized according to the longitudinal electron mass (X/sub 1/). Strain shifts at the X-points are of the same magnitude as quantum size effect shifts and drive the X/sub t/ band toward lower energies. The effect of strain in the conduction band can be accurately modeled by assuming GaP deformation potentials for the AlAs layers.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 7077198
- Report Number(s):
- SAND-86-2724C; CONF-870385-3; ON: DE87006891
- Resource Relation:
- Conference: SPIE conference on growth of compound semiconductors, Bay Point, FL, USA, 26 Mar 1987; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM ARSENIDES
ELECTRONIC STRUCTURE
SUPERLATTICES
GALLIUM ARSENIDES
LAYERS
PHOTOLUMINESCENCE
STRAINS
X-RAY DIFFRACTION
ALUMINIUM COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
COHERENT SCATTERING
DIFFRACTION
GALLIUM COMPOUNDS
LUMINESCENCE
PNICTIDES
SCATTERING
360602* - Other Materials- Structure & Phase Studies