DMMP Sensing Performance of Undoped and Al Doped Nanocrystalline ZnO Thin Films Prepared by Ultrasonic Atomization and Pyrolysis Method

Abstract

Highly textured undoped (pure) and Al doped ZnO nanocrystalline thin films prepared by ultrasonic atomization and pyrolysis method are reported in this paper. ZnCl2 water solution was converted into fine mist by ultrasonic atomizer (Gapusol 9001 RBI Meylan, France). The mist was pyrolyzed on the glass substrates in horizontal quartz reactor placed in furnace. The Structural and microstructural properties of the films were characterized by X-Ray Diffractometer (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). FESEM and TEM analysis revealed that the ZnO thin films prepared were porous monodisperse and nanocrystalline in nature, with average particle size of 15 nm. The optical properties of thin films were characterized by UV-Visible and Photoluminescence (PL) spectroscopy. The films were cut in typical size and electrical contactswere made using silver paste and copper wires. The thin film based sensors so prepared were tested on exposing the simulants of chemical warfare agent (CWA) like: DMMP, CEES and CEPS. Sensors showed better response to DMMP (a simulant of sarin gas) as compared with its responses to CEES and CEPS. Al (1 at%) doped ZnO thin film based sensor showed highest response to DMMP (2 ppm). The simulant response, selectivity and response-recovery time of the sensors were measured and presented. The role of Al dopant in ZnO to enhance DMMP response is discussed.