Molecular beam epitaxy and structural anisotropy of m-plane InN grown on free-standing GaN

Journal Article · Mon Oct 27 04:00:00 EDT 2008 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.3001806· OSTI ID:21175691

Koblmueller, G; Hirai, A; Wu, F; Gallinat, C S; Speck, J S ^[1]; Metcalfe, G D; Shen, H; Wraback, M ^[2]

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1. Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)
2. U. S. Army Research Laboratory, Sensors and Electron Devices Directorate, 2800 Powder Mill Road, Adelphi, Maryland 20783 (United States)

This study reports on the growth of high-quality nonpolar m-plane [1100] InN films on free-standing m-plane GaN substrates by plasma-assisted molecular beam epitaxy. Optimized growth conditions (In/N ratio {approx}1 and T=390-430 deg. C) yielded very smooth InN films with undulated features elongated along the [1120] orientation. This directionality is associated with the underlying defect structure shown by the anisotropy of x-ray rocking curve widths parallel to the [1120] (i.e., 0.24 deg. - 0.34 deg.) and [0001] (i.e., 1.2 deg. - 2.7 deg.) orientations. Williamson-Hall analysis and transmission electron microscopy identified the mosaic tilt and lateral coherence length and their associations with different densities of dislocations and basal-plane stacking faults. Ultimately, very low band gap energies of {approx}0.67 eV were measured by optical absorption similar to the best c-plane InN.

• OSTI ID: 21175691
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 17 Vol. 93; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION
ANISOTROPY
COHERENCE LENGTH
CRYSTAL GROWTH
CRYSTALS
DISLOCATIONS
FILMS
GALLIUM NITRIDES
GRAIN ORIENTATION
INDIUM NITRIDES
MOLECULAR BEAM EPITAXY
SEMICONDUCTOR MATERIALS
STACKING FAULTS
SUBSTRATES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION