Lattice parameters and electronic structure of BeMgZnO quaternary solid solutions: Experiment and theory

Journal Article · Mon Mar 07 00:00:00 EST 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4942835· OSTI ID:22597031

Toporkov, M.; Avrutin, V.; Morkoç, H.; Özgür, Ü. ^[1]; Demchenko, D. O. ^[2]; Zolnai, Z. ^[3]; Volk, J. ^[1]

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1. Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)
2. Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)
3. MTA EK Institute of Technical Physics and Materials Science, Budapest (Hungary)

Be{sub x}Mg{sub y}Zn{sub 1−x−y}O semiconductor solid solutions are attractive for UV optoelectronics and electronic devices owing to their wide bandgap and capability of lattice-matching to ZnO. In this work, a combined experimental and theoretical study of lattice parameters, bandgaps, and underlying electronic properties, such as changes in band edge wavefunctions in Be{sub x}Mg{sub y}Zn{sub 1−x−y}O thin films, is carried out. Theoretical ab initio calculations predicting structural and electronic properties for the whole compositional range of materials are compared with experimental measurements from samples grown by plasma assisted molecular beam epitaxy on (0001) sapphire substrates. The measured a and c lattice parameters for the quaternary alloys Be{sub x}Mg{sub y}Zn{sub 1−x} with x = 0−0.19 and y = 0–0.52 are within 1%–2% of those calculated using generalized gradient approximation to the density functional theory. Additionally, composition independent ternary BeZnO and MgZnO bowing parameters were determined for a and c lattice parameters and the bandgap. The electronic properties were calculated using exchange tuned Heyd-Scuseria-Ernzerhof hybrid functional. The measured optical bandgaps of the quaternary alloys are in good agreement with those predicted by the theory. Strong localization of band edge wavefunctions near oxygen atoms for BeMgZnO alloy in comparison to the bulk ZnO is consistent with large Be-related bandgap bowing of BeZnO and BeMgZnO (6.94 eV). The results in aggregate show that precise control over lattice parameters by tuning the quaternary composition would allow strain control in Be{sub x}Mg{sub y}Zn{sub 1−x−y}O/ZnO heterostructures with possibility to achieve both compressive and tensile strain, where the latter supports formation of two-dimensional electron gas at the interface.

• OSTI ID: 22597031
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 9; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BOWING
COMPARATIVE EVALUATIONS
DENSITY FUNCTIONAL METHOD
ELECTRON GAS
ELECTRONIC EQUIPMENT
ELECTRONIC STRUCTURE
ELECTRONS
LATTICE PARAMETERS
MOLECULAR BEAM EPITAXY
MOLECULAR BEAMS
OXYGEN
QUATERNARY ALLOY SYSTEMS
SAPPHIRE
SEMICONDUCTOR MATERIALS
SOLID SOLUTIONS
SOLIDS
THIN FILMS
TWO-DIMENSIONAL CALCULATIONS
WAVE FUNCTIONS
ZINC OXIDES