Influence of growth temperature on electrical, optical, and plasmonic properties of aluminum:zinc oxide films grown by radio frequency magnetron sputtering

Journal Article · Mon Oct 14 04:00:00 EDT 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4824751· OSTI ID:22217934

Dondapati, Hareesh; Santiago, Kevin; Pradhan, A. K. ^[1]

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1. Center for Materials Research, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)

We have investigated the responsible mechanism for the observation of metallic conductivity at room temperature and metal-semiconductor transition (MST) at lower temperatures for aluminum-doped zinc oxide (AZO) films. AZO films were grown on glass substrates by radio-frequency magnetron sputtering with varying substrate temperatures (T{sub s}). The films were found to be crystalline with the electrical resistivity close to 1.1 × 10{sup −3} Ω cm and transmittance more than 85% in the visible region. The saturated optical band gap of 3.76 eV was observed for the sample grown at T{sub s} of 400 °C, however, a slight decrease in the bandgap was noticed above 400 °C, which can be explained by Burstein–Moss effect. Temperature dependent resistivity measurements of these highly conducting and transparent films showed a MST at ∼110 K. The observed metal-like and metal-semiconductor transitions are explained by taking into account the Mott phase transition and localization effects due to defects. All AZO films demonstrate crossover in permittivity from positive to negative and low loss in the near-infrared region, illustrating its applications for plasmonic metamaterials, including waveguides for near infrared telecommunication region. Based on the results presented in this study, the low electrical resistivity and high optical transmittance of AZO films suggested a possibility for the application in the flexible electronic devices, such as transparent conducting oxide film on LEDs, solar cells, and touch panels.

• OSTI ID: 22217934
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 14 Vol. 114; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
MAGNETRONS
PERMITTIVITY
PHASE TRANSFORMATIONS
RADIOWAVE RADIATION
SEMICONDUCTOR MATERIALS
SOLAR CELLS
SPUTTERING
SUBSTRATES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
WAVEGUIDES
ZINC OXIDES