Tellurium Thin Films in Sensor Technology

An extensive review of the application of tellurium thin films in sensor technology is reported and discussed. Along with the traditional use of Te films in photo and strain sensitive devices, their modern application in chemical gas sensors is considered in detail. Fabrication parameters such as the technology of preparation, the substrate material, the thickness and morphology of the samples are shown to influence the response to gases. The effect of these parameters as well as that of temperature and thermal treatments on sensitivity, response and recovery times is discussed with respect to the structural evolution of the films, studied by SEM, XRD and XPS analyses. Further, the characterization of Te thin films for the detection of NO2, NH3 and H2S as well as their cross-sensitivity to the main components of the atmosphere (O-2, N-2 and H2O vapor) at different temperatures is given. The sensing mechanism is explained and the state of the art in the development of Te-based gas sensors operating at room temperature is considered.