Sensitivity to vapors of ethanol of thin films of SnO2 alloyed by fluorine after isothermal annealing

Abstract

Films of tin oxide are intensively used as a sensitive element of sensors for the determination of various gases in atmospheric air [1]. The principle of operation of these sensors is based on the modulation of the near-surface space charge region and the change in the electrical resistivity of film crystals upon adsorption of gas molecules. In order for physicochemical processes to proceed quickly on the surface of the sensitive layer, providing a response time of several seconds, the sensor is heated to a temperature of 100-450 ° C, which "activates" its surface. Sensors are used by environmental services, chemical enterprises, in oil and gas industry - wherever it is necessary to make express measurements of the concentrations of such gases as: propane, methane, hydrogen, vapors of ethyl alcohol. For a long time, thin films are in a state heated to 400°C. Determining how long the film can retain its useful properties in the operating mode is an actual scientific and practical task.