Far-IR Sb-O vibrations in annealed sputtered films of Sb2Te3 for thermoelectric THz detector applications

Our antenna-coupled thermoelectric THz detectors use sputtered Sb2Te3 films as one of the key materials. After sputtering at room temperature, films must be activated by annealing, which introduces Sb-O infrared vibrational bands for temperatures exceeding ~ 200 °C. Far-infrared reflectance spectra and X-ray diffraction data suggest that the oxidation occurs mainly at the interface between film and glass substrate and does not affect the bulk of the film. Detector characterization data is presented for antenna-coupled Sb2Te3-Bi2Te3 thermoelectric junction detectors.