Surface spectroscopy of the CdSe and CdS thin film sensors of oxygen

Two principal forms of oxygen chemisorption on the surface of CdSe and CdS gas sensors have been revealed by X-ray photoelectron spectroscopy and thermal desorption mass spectrometry experiments. For the chemisorbed O-2(-), the characteristic binding energy of the O 1s electrons is found to be 531.8+/-0.2 eV and for the chemisorbed O-, 531.1+/-0.2 eV. The concentration of the chemisorbed oxygen increases when the surface of the investigated sensor is enriched or doped with metal atoms.