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Title: Optical and structural properties of molecular-beam epitaxial GaAs on sapphire

Technical Report ·
OSTI ID:5551111

The structural and optical properties of GaAs grown by molecular-beam epitaxy on (0001) and (01{bar 1}2)-oriented sapphire substrates are evaluated for possible direct deposition on sapphire optical fibers and optoelectronic device applications. X-ray diffraction studies and cross-sectional transmission electron-microscopy measurements show that the GaAs films are single-crystal and have a (111) orientation for both substrate orientations. Both x-ray and temperature-dependent photoluminescence measurements indicate that the quality of the GaAs films is better for the (01{bar 1}2) sapphire orientation. The incorporation of a graded-band-gap strained layer in InGaAs/GaAs superlattice near the sapphire-GaAs interface also improves the optical quality of the GaAs films. Low-temperature photoluminescence spectra is dominated by a peak at 1.49-1.495 eV, with a best linewidth of 26.9 meV, which is due to an integration of several impurity- and defect-related bound-exciton transitions. A peak-to-lower energies by about 60 meV is thought to be due to acceptor-like impurity defect complexes. Post-growth short-term halogen lamp annealing marginally improves the overall luminescence intensity of the samples. A linewidth of 20 meV is measured for a (80 A) GaAs/(120A)Al(0.3)Ga(0.7)As multiquantum grown on sapphire. It is apparent that device-quality single-crystal GaAs and GaAs-related compounds can be deposited directly on sapphire substrates by molecular beam epitaxy, using special growth techniques.

Research Organization:
Michigan Univ., Ann Arbor, MI (USA). Solid-State Electronics Lab.
OSTI ID:
5551111
Report Number(s):
AD-A-209430/8/XAB
Resource Relation:
Other Information: Pub. in Jnl. of Vacuum Science Technology, Vol. B7, No. 2, 283-288(Mar/Apr 1989)
Country of Publication:
United States
Language:
English