Influence of Cation Ratio and Oxygen Deposition Pressure on Optical and Electrical Transport Properties of Amorphous Copper Tin Oxide Thin Films

Amorphous copper tin oxide thin films are fabricated in oxygen atmosphere and at room temperature using combinatorial pulsed laser deposition approaches. Resulting thin films show n‐type behavior for Cu/(Cu + Sn) < 0.5. For Cu/(Cu + Sn) > 0.7, p‐type behavior is observed by qualitative Seebeck effect measurements; however, the electrical resistivity is too high for Hall effect measurements. Structural, optical, and electrical thin film properties are investigated in dependence on the cation composition and oxygen deposition pressure. An extended percolation‐based random band edge model is applied to the temperature‐dependent conductivity and Hall effect measurements for different deposition pressures. Extracted fit parameters are in a similar range to those reported for other amorphous oxide semiconductors. In particular, the band‐disorder parameter, specifying the width of the Gaussian band edge distribution for long‐range potential fluctuations, is identified as leading parameter for determining the optical and electrical properties of the thin films.