Epitaxial growth, electrical and optical properties of a-plane InN on r-plane sapphire

Journal Article · Fri Jan 15 00:00:00 EST 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3284086· OSTI ID:21476114

Ajagunna, A O; Iliopoulos, E; Tsiakatouras, G; Tsagaraki, K; Androulidaki, M; Georgakilas, A ^[1]

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1. Microelectronics Research Group, IESL, FORTH, P.O. Box 1385, 71110 Heraklion-Crete (Greece)

The heteroepitaxy of a-plane (1120) InN films on r-plane (1102) sapphire substrates, by nitrogen radio frequency plasma-assisted molecular beam epitaxy, has been investigated and compared to that of c-plane (0001) InN. The epitaxial growth of a-plane InN proceeded through the nucleation, growth, and coalescence of three-dimensional islands, resulting in surface roughness that increased monotonically with epilayer thickness. The full width at half maximum of (1120) x-ray diffraction rocking curves decreased significantly with increasing InN thickness, characteristic of structural improvement, and it reached the value of 24 arcmin for a 1 {mu}m thick film. Hall-effect measurements exhibited a similar dependence of electron concentration and mobility on thickness for both the a- and c-plane InN films. The analysis of the Hall-effect measurements, by considering the contribution of two conducting layers, indicates a similar accumulation of low mobility electrons with N{sub s}>10{sup 14} cm{sup -2} at the films' surface/interfacial region for both the a- and c-plane InN films. From optical transmittance measurements, the absorption edge of 0.768 eV was determined for the 1 {mu}m a-plane film, consistent with the expected Burstein-Moss effect. Photoluminescence spectra exhibited a lower energy peak at 0.631 eV, suggesting defect-related transitions.

• OSTI ID: 21476114
• Journal Information: Journal of Applied Physics, Vol. 107, Issue 2; Other Information: DOI: 10.1063/1.3284086; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COALESCENCE
ELECTRON DENSITY
ELECTRON MOBILITY
EMISSION SPECTRA
HALL EFFECT
INDIUM NITRIDES
MOLECULAR BEAM EPITAXY
NEUTRON DIFFRACTION
NITROGEN
OPTICAL PROPERTIES
PHOTOLUMINESCENCE
SAPPHIRE
SEMICONDUCTOR MATERIALS
SUBSTRATES
SURFACES
THIN FILMS
X-RAY DIFFRACTION
COHERENT SCATTERING
CORUNDUM
CRYSTAL GROWTH METHODS
DIFFRACTION
ELEMENTS
EMISSION
EPITAXY
FILMS
INDIUM COMPOUNDS
LUMINESCENCE
MATERIALS
MINERALS
MOBILITY
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
OXIDE MINERALS
PARTICLE MOBILITY
PHOTON EMISSION
PHYSICAL PROPERTIES
PNICTIDES
SCATTERING
SPECTRA