A comparative study of electronic and structural properties of polycrystalline and epitaxial magnetron-sputtered ZnO:Al and Zn{sub 1-x}Mg{sub x}O:Al Films—Origin of the grain barrier traps

Journal Article · Wed Aug 14 04:00:00 EDT 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4817376· OSTI ID:22218236

Bikowski, André; Ellmer, Klaus ^[1]

---

1. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Solar Fuels, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany)

Homoepitaxial and heteroepitaxial ZnO, ZnO:Al, and Zn{sub 1-x}Mg{sub x}O:Al films have been grown by magnetron sputtering from ceramic targets at substrate temperatures between 200 °C and 500 °C. We studied the relation between the electronic transport and structural properties for the epitaxially grown films and compared it to the properties of polycrystalline films by means of X-ray diffraction, transmission electron microscopy and optical reflectance and transmittance measurements. The results show that the epitaxial growth of ZnO:Al and Zn{sub 1-x}Mg{sub x}O:Al thin films, which has been observed for nearly all films prepared on single crystalline substrates, will not significantly improve the electronic transport properties in comparison to polycrystalline films unless the grain boundaries are eliminated completely. The grain boundary defect densities of about 3 × 10{sup 13} cm{sup −2} are nearly independent on the structural quality of the different polycrystalline, hetero- and homoepitaxial films. This clearly proves that the grain boundary defects are not caused by crystallographic defects, but, most probably, by the dopant aluminium.

• OSTI ID: 22218236
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 6 Vol. 114; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
EPITAXY
GRAIN BOUNDARIES
MAGNETRONS
POLYCRYSTALS
SEMICONDUCTOR MATERIALS
SPUTTERING
SUBSTRATES
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
ZINC OXIDES