Thin films of Si1-xGex and Si1-xGexOy were deposited by radio frequency (rf) magnetron sputtering at room temperature from a single target of Si1-xGex in the Ar or Ar:O-2 environment. The silicon and oxygen concentrations were varied in a parametric investigation of the dependence of the electrical and optical characteristics of the thin films on composition. As Si concentration was increased in the Si1-xGex films, the temperature coefficient of resistance (TCR) was decreased. For Si1-xGexOy films, the addition of oxygen to the Si1-xGex, increased the activation energy and TCR. The TCR was measured to vary from -2.27% to -8.69%/K. The optical bandgap was increased with the increasing concentration of oxygen in Si1-xGexOy. A suitable atomic composition of Si1-xGexOy for uncooled infrared detector applications was found to have a TCR of -5.10%/K. (c) 2006 Elsevier B.V. All rights reserved.