IN-SITU DIFFUSE-REFLECTANCE INFRARED-SPECTROSCOPY (DRIFTS) STUDY OF THE REVERSIBILITY OF CDGEON SENSORS TOWARDS OXYGEN

A novel diffuse reflectance infrared spectroscopy (DRIFTS) chamber, sp ecially designed for in situ and simultaneous infrared and conductance analysis of sensors, is described in this paper. The capabilities of this new tool are shown through the study of the reversible behaviour versus temperature of a CdGeON sensor under N-2 and synthetic-air atmo spheres. The conductance of the sensor is directly related to the pres ence of DRIFTS bands at 810, 780 and 580 cm(-1) assigned to oxygenated species directly bonded to single Ge atoms. These species are elimina ted or restored in the solid network upon heating under N-2 or synthet ic air, respectively. From the analysis of the resistance-temperature Arrhenius-type relationships, the influence of the atmosphere on the c onduction mechanism is discussed.