Fe Doped WO3 Thin films Prepared by Spray Pyrolysis towards Ethanol Sensing

Abstract

WO 3 and Fe doped WO 3 thin films were deposited on glass substrate using spray pyrolysis technique. The structural properties reveals the crystalline nature with preferred oriented (200) plane along c-axis direction. There is a shift in the band edge towards longer wavelength after Fe incorporation is confirmed from optical properties. Compare to WO 3 , Fe doped WO 3 shows large sensor response towards ethanol.3 Introduction:Medical detection, environmental protection and food industries give a prior place to ethanol sensors. Ethanol present in human breath can be easily detected by breath alcohol analysis in which detection of ethanol is an important feature 1 . Present researches include the development of ethanol sensors at lower operating temperature with better selectivity and sensitivity. Metal oxide semiconductors (MOS) promises a new generation of gas sensing devices among which tungsten trioxide WO 3 has great attention 2,3 . WO 3 doped with other elements has high performance and efficiency. The sensing properties of the film can be upgraded significantly which becomes the main objective of doping the films with catalytic ion in presence of ethanol. However no enhancement of ethanol sensing performance of with the catalytic doping was observed.Fe is one of the most warrant materials with WO 3 to enhance the physical and chemical properties for optoelectronics device application 4 . Compare to other techniques, spray pyrolysis is the most suitable method to produce metal oxide thin film with huge number of pores and fabricate metal oxide sensors. The growth of the film use a novel spray pyrolysis deposition route with a spray nozzle and crystal structure, optical properties of Fe doped WO 3 were investigated. Experimental ProcedurePristine and Fe activated films fabricated on glass substrate at 400 route using (0.3 M) tungsten chloride 0.5 iron chloride precursor. The carrier gas flow rate is fixed at 0.3 Kg cm 2 . The precursor volume is 100 ml using the solvent ethanol and solution feeding rate is 4 ml/min. The distance between the substrate and the spray nozzle is kept 20 cm with the deposition time of 12 min. The spray nozzle is designed in such a way