Optical and dielectric properties of CuAl2O4 films synthesized by solid-phase epitaxy

• Published in: Thin solid films Vol. 515; no. 17; pp. 6938 - 6942
• Main Authors: LEU, L. C, NORTON, D. P, JELLISON, G. E, SELVAMANICKAM, V, XIONG, X
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier Science 01.06.2007
• Subjects: ALUMINIUM OXIDES; Condensed matter: electronic structure, electrical, magnetic, and optical properties; COPPER OXIDES; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; DIELECTRIC PROPERTIES; Dielectric thin films; Dielectrics, piezoelectrics, and ferroelectrics and their properties; ENERGY GAP; Exact sciences and technology; MAGNESIUM OXIDES; MATERIALS SCIENCE; Methods of deposition of films and coatings; film growth and epitaxy; OPACITY; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Solid phase epitaxy; growth from solid phases; SPUTTERING; SUBSTRATES; THIN FILMS; Electronic properties; Amorphous thin film; Dielectric properties; Solid-phase epitaxy; O; Energy gap; Monocrystals; Optical transmission; Spinels; Optical properties; Dielectric thin films; Solid-phase epitaxy; Spinel; Dielectrics; Oxide; Physical vapor deposition; Magnesium oxides; 73.61.-r; 78.20.Ci; 78.66.-w; 81.15.Cd; 81.15.Np; Absorption spectra; Thermal annealing; CuAl
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2007.02.012

The synthesis and properties of CuAl{sub 2}O{sub 4} thin films have been examined. The CuAl{sub 2}O{sub 4} films were deposited via reactive direct current magnetron sputter using a CuAl{sub 2} target. As-deposited films were amorphous. Post-deposition annealing at high temperature in oxygen yielded solid-phase epitaxy on MgO. The film orientation was cube-on-cube epitaxy on (001) MgO single-crystal substrates. The films were transparent to visible light. The band gap of crystalline CuAl{sub 2}O{sub 4} was determined to be {approx} 4 eV using a Tauc plot from the optical transmission spectrum. The dielectric constant of the amorphous films was determined to be {approx} 20-23 at 1-100 kHz.