AVS 50th International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeP

Paper TF-WeP9
P-Type Semiconducting Cu@sub 2@O-NiO Thin Films Prepared by Magnetron Sputtering

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: T. Shimakawa, Kanazawa Institute of Technology, Japan
Authors: T. Minami, Kanazawa Institute of Technology, Japan
H. Tanaka, Kanazawa Institute of Technology, Japan
T. Shimakawa, Kanazawa Institute of Technology, Japan
Correspondent: Click to Email
This report describes the preparation of p-type semiconducting thin films consisting of a new multicomponent oxide, Cu@sub 2@O-NiO. The Cu@sub 2@O-NiO films were deposited on glass substrates at a temperature of 200-500@super o@C by r.f. magnetron sputtering carried out at a pressure of 0.2-2.0 Pa in an Ar or O@sub 2@ gas atmosphere with an r.f. power of 80 W using a powder target. A mixture of Cu@sub 2@O and NiO powders calcined at 1000@super o@C in an Ar or air atmosphere for 1 h was used as the target: Ni contents (Ni/(Cu+Ni) atomic ratio) in the range from 0 to 100 at.%. The obtained electrical and optical properties of Cu@sub 2@O-NiO thin films were strongly dependent on the deposition conditions as well as the Ni content of the target. P-type semiconducting Cu@sub 2@O-NiO thin films could be prepared at 500@super o@C in a pure Ar gas atmosphere at a pressure of 0.4 Pa using targets calcined in Ar: All the prepared Cu@sub 2@O-NiO thin films were found to exhibit positive hole conduction, as evidenced from Hall measurements and the Seebeck effect. The resistivity of the Cu@sub 2@O-NiO thin films prepared under the above conditions increased markedly as the Ni content was increased up to about 30 at.%, remained relatively constant in the range of about 30 to 60 at.%, and then increased markedly with further increases of Ni content. In the Cu@sub 2@O-NiO thin films prepared with an increasing Ni content in the range from 0 to 30 at.%, the obtained resistivity increased from 70 to 4×10@super 4@@ohm@cm, resulting from decreases in both Hall mobility and hole concentration, and band-gap energy increased from 2.6 to 2.9 eV. In contrast, the Cu@sub 2@O-NiO thin films prepared with a Ni content in the range from 30 to 50 at.% exhibited a relatively constant resistivity on the order of 3×10@super 4@@ohm@cm; these films were identified as the ternary compounds NiCuO@sub 2@ or Ni@sub 2@CuO@sub 3@, by x-ray diffraction analyses. The multicomponent oxide Cu@sub 2@O-NiO thin films prepared by r.f. magnetron sputtering with a Ni content in the range from 0 to 100 at.% were found to be p-type semiconductors with a resistivity that was increased by increasing Ni content. From spectroscopic ellipsometric measurements, it was found that the band-gap energy of Cu@sub 2@O-NiO films can be controlled in the range from 2.6 to 4 eV.