Smooth cubic commensurate oxides on gallium nitride

Journal Article · Fri Feb 14 00:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4861172· OSTI ID:22278078

Paisley, Elizabeth A.; Gaddy, Benjamin E.; LeBeau, James M.; Shelton, Christopher T.; Losego, Mark D.; Mita, Seiji; Collazo, Ramón; Sitar, Zlatko; Irving, Douglas L.; Maria, Jon-Paul ^[1]; Biegalski, Michael D.; Christen, Hans M. ^[2]

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1. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)
2. Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

Smooth, commensurate alloys of 〈111〉-oriented Mg{sub 0.52}Ca{sub 0.48}O (MCO) thin films are demonstrated on Ga-polar, c+ [0001]-oriented GaN by surfactant-assisted molecular beam epitaxy and pulsed laser deposition. These are unique examples of coherent cubic oxide|nitride interfaces with structural and morphological perfection. Metal-insulator-semiconductor capacitor structures were fabricated on n-type GaN. A comparison of leakage current density for conventional and surfactant-assisted growth reveals a nearly 100× reduction in leakage current density for the surfactant-assisted samples. HAADF-STEM images of the MCO|GaN interface show commensurate alignment of atomic planes with minimal defects due to lattice mismatch. STEM and DFT calculations show that GaN c/2 steps create incoherent boundaries in MCO over layers which manifest as two in-plane rotations and determine consequently the density of structural defects in otherwise coherent MCO. This new understanding of interfacial steps between HCP and FCC crystals identifies the steps needed to create globally defect-free heterostructures.

• OSTI ID: 22278078
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CALCIUM OXIDES
COMPARATIVE EVALUATIONS
CRYSTAL DEFECTS
CRYSTALS
DENSITY
ELECTRON MICROSCOPY
ENERGY BEAM DEPOSITION
FCC LATTICES
GALLIUM NITRIDES
HCP LATTICES
HETEROJUNCTIONS
INTERFACES
LASER RADIATION
LAYERS
LEAKAGE CURRENT
MAGNESIUM COMPOUNDS
MOLECULAR BEAM EPITAXY
PULSED IRRADIATION
SEMICONDUCTOR MATERIALS
THIN FILMS