AVS 49th International Symposium
    Thin Films Monday Sessions
       Session TF-MoA

Paper TF-MoA3
p-Type Semiconducting Cu@sub 2@O-CoO Thin Films Prepared by Magnetron Sputtering

Monday, November 4, 2002, 2:40 pm, Room C-101

Session: Transparent Conductive Coatings
Presenter: S. Suzuki, Kanazawa Institute of Technology, Japan
Authors: S. Suzuki, Kanazawa Institute of Technology, Japan
T. Miyata, Kanazawa Institute of Technology, Japan
T. Minami, Kanazawa Institute of Technology, Japan
Correspondent: Click to Email
In this report, we describe the preparation by magnetron sputtering of p-type semiconducting thin films consisting of a new multicomponent oxide, Cu@sub 2@O-CoO. The Cu@sub 2@O-CoO films (thickness, 200-450 nm) were deposited on glass substrates at a temperature of 200 to 400@super o@C by r.f. magnetron sputtering using a powder target. The sputtering deposition was carried out at a pressure of 0.2 to 4.0 Pa in an Ar+O@sub 2@ gas atmosphere with an r.f. power up to about 80 W. A mixture of Cu@sub 2@O and CoO powders calcined at 1000@super o@C in air for 1 h was used as the target: CoO contents of 0 to 100 mol.%. The obtained electrical and optical properties were strongly dependent on the deposition conditions as well as the CoO content of the target. The resistivity of Cu@sub 2@O-CoO thin films deposited at 200@super o@C in a pure O@sub 2@ gas atmosphere at a pressure of 2.0 Pa with an r.f. power of 80 W decreased as the CoO content was increased, reached a minimum at about 80 mol.%, and then increased markedly with a further increase in CoO content. A minimum resistivity of 3.9X10@super ?3@@ohm@cm was obtained in a Cu@sub 2@O-CoO thin film prepared with a CoO content of 80 mol.% and identified as the polycrystalline delafossite CuCoO@sub 2@ by x-ray diffraction analyses. However, the resistivity exhibited a spatial distribution on the substrate surface that depended on the deposition conditions. The multicomponent oxide Cu@sub 2@O-CoO thin films prepared in the CoO content range from 0 to 100 mol.% found to be p-type, or positive hole conduction, as evidenced from Seebeck effect. From transmission spectra measurements, the band-gap energy of Cu@sub 2@O-CoO films are roughly estimated to be about 1.8 eV. This is the first report of the preparation of new p-type semiconducting Cu@sub 2@O-CoO thin films.