Competition between (001) and (111) MgO thin film growth on Al-doped ZnO by oxygen plasma assisted pulsed laser deposition

Journal Article · Fri Jun 07 04:00:00 EDT 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4807933· OSTI ID:22162990

Xiao, Bo; Yang, Qiguang; Walker, Brandon; Gonder, Casey A.; Romain, Gari C.; Mundle, Rajeh; Bahoura, Messaoud; Pradhan, A. K. ^[1]

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1. Center for Materials Research, Norfolk State University, Norfolk, Virginia 23504 (United States)

We report on the study of epitaxial MgO thin films on (0001) Al-doped ZnO (Al: ZnO) underlayers, grown by oxygen plasma assisted pulsed laser deposition technique. A systematic investigation of the MgO thin films was performed by X-ray diffraction and atomic force microscopy, along with the current-voltage characteristics. A distinguished behavior was observed that the preferred MgO orientation changes from (111) to (001) in the films as the growth temperature increases. Two completely different in-plane epitaxial relationships were also determined from X-ray diffraction as: [110]MgO//[1120]Al: ZnO and [110]MgO//[1100]Al: ZnO for (001) MgO with 60 Degree-Sign rotated triplet domains, and [110]MgO//[1120]Al: ZnO for (111) MgO with 180 Degree-Sign rotated twin. The pronounced temperature dependence indicates a reconciliation of the nucleation driving forces among surface, interfacial, and strain energy for heteroepitaxy of cubic MgO on hexagonal Al: ZnO. The related interfacial atomic registry is considered to be important to the formation of unusual (001) MgO on hexagonal crystals. In addition, the electrical characterization revealed a dramatic reduction of the leakage current in (001) MgO thin films, whereas the small grain size of (111) MgO is identified by atomic force microscopy as a main cause of large leakage current.

• OSTI ID: 22162990
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 21 Vol. 113; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM ADDITIONS
ATOMIC FORCE MICROSCOPY
CRYSTALS
DOPED MATERIALS
ENERGY BEAM DEPOSITION
GRAIN SIZE
LASER RADIATION
LAYERS
LEAKAGE CURRENT
MAGNESIUM OXIDES
PULSED IRRADIATION
SURFACE ENERGY
SURFACES
TEMPERATURE DEPENDENCE
THIN FILMS
VAPOR PHASE EPITAXY
X-RAY DIFFRACTION
ZINC OXIDES