Properties of copper-scandium oxide thin films prepared by pulsed laser deposition

We fabricated a CuScO2 thin film on an alpha-Al2O3(1 1 (2) over bar 0) substrate by the pulsed laser deposition method using a single-phase Cu2Sc2O5 target, and investigated the effect of oxygen pressure on the film quality. Under optimized oxygen pressure, we obtained a single-phase CuScO2 thin film whose crystalline structure was the rhombohedral system. The film showed a strong c-axis orientation. The optical transmittance of the film was greater than 70% in the visible/near-infrared region, while the energy gap for direct allowed transition was estimated to be 3.7 eV The resistivity (rho) was 8.6 x 10(3) Omega cm at room temperature, and log rho was proportional to T-1/4 below 250 K. This suggests that a variable-range hopping mechanism is dominant below 250 K. (C) 2003 Elsevier Science B.V. All rights reserved.