SnO2 thin film synthesis for organic vapors sensing at ambient temperature

The present work is a study of tin dioxide (SnO2) based thin sensitive layer dedicated to organic vapors detection at ambient temperature. SnO2 thin film was deposited by chemical spray pyrolysis technique. The glass substrate temperature was kept to 400 °C, using a starting solution of 0.1 M tin (II) dichloride dihydrate (SnCl2, 2H2O). Films structural and morphological properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscope (AFM) respectively. Films optical characteristics were studied using UV-VIS spectrophotometer. XRD revealed the presence of pure SnO2 polycrystalline thin film with a tetragonal rutile structure. The SEM and AFM observations confirmed the granular morphology with presence of pores in the film surface. The prepared film was tested in various organic vapors (ethanol, methanol and acetone) at ambient operating temperature (25 °C ± 2 °C). The obtained results suggested that SnO2 is more sensitive to ethanol vapor with a maximum sensitivity of 35% higher than to methanol and acetone vapors (1% and 3%). The realized SnO2 based sensor demonstrated fast response and recovery times as revealed by the values of 2 s to 3 s towards 47 ppm of ethanol vapor.