ZnO and Al-doped ZnO thin films prepared by spray pyrolysis for ethanol gas sensing

Laboratory of Electron Microscopy and Materials Sciences, University of Science and Technology of Oran, P.O. Box 1505, 31000 El-Mnaouer Oran, Algeria

^a e-mail: s97soriia@gmail.com

Received: 19 February 2011
Revised: 4 May 2011
Accepted: 30 May 2011
Published online: 18 August 2011

Abstract

Chemically sprayed aluminum-doped ZnO (1% Al) and undoped ZnO thin films were deposited on glass substrates at T = 420 °C. The thin films are characterized by X-ray diffraction and scanning electron microscopy. The characterization results show that all the compounds are wurtzite with hexagonal structure (0 0 2). They are well crystallized and the grain size is (e = 0.1 μm) for undoped ZnO and (e = 0.13 μm) for Al-doped ZnO. The prepared Al-doped ZnO showed good gas responses to ethanol for two concentrations 200 ppm and 400 ppm. Short response time is given by Al-doped ZnO comparing with undoped ZnO films, its estimate at (~10 s) and recovery time (~15 s) to 200 ppm at T = 220 °C.