Optical investigation of Zn{sub 1-x}Fe{sub x}O films grown on Al{sub 2}O{sub 3}(0001) by radio-frequency sputtering

Journal Article · Fri Oct 15 04:00:00 EDT 2004 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1790570· OSTI ID:20662104

Kim, Kwang Joo; Park, Young Ran ^[1]

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1. Department of Physics and Center for Optoelectronic and Microwave Devices, Konkuk University, Seoul 143-701 (Korea, Republic of)

Zn{sub 1-x}Fe{sub x}O thin films were grown on Al{sub 2}O{sub 3}(0001) substrates by radio-frequency magnetron sputtering. The alloys show wurtzite crystal structure up to x=0.24 with reduced c-axis lattice constant compared to that of pure ZnO. Fe 2p core-level photoemission measurements reveal the evidence for the coexistence of the Fe{sup 3+} and Fe{sup 2+} ions substituting the tetrahedral the Zn{sup 2+} sites. The optical properties of the samples were measured by the spectroscopic ellipsometry at room temperature in the 1.5-5 eV photon energy region. With increasing x, the optical band-gap (E{sub 0}) absorption edge is found to shift slightly to lower energies (70 meV for x=0.24) than that of the pure ZnO. Below the E{sub 0} edge, optical absorption structures are observed at about 1.7, 2.4, and 2.8 eV. These structures are interpreted as due to the d-d transitions from the {sup 6}A{sub 1} ground state to the excited states, {sup 4}T{sub 1} (1.7 eV), {sup 4}T{sub 2} (2.4 eV), and {sup 4}E and {sup 4}A{sub 1} (2.8 eV), of the crystal-field-split 3d{sup 5} multiplets of the tetrahedral Fe{sup 3+} ion.

• OSTI ID: 20662104
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 96; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION
ALUMINIUM OXIDES
CRYSTAL FIELD
CRYSTAL STRUCTURE
ELLIPSOMETRY
EV RANGE 01-10
EXCITED STATES
FERROMAGNETIC MATERIALS
IRON IONS
IRON OXIDES
LATTICE PARAMETERS
MEV RANGE 10-100
PHOTOEMISSION
SEMICONDUCTOR MATERIALS
SPUTTERING
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
X-RAY PHOTOELECTRON SPECTROSCOPY
ZINC IONS
ZINC OXIDES