Effect of Pt doping on the gas sensing properties of porous chromium oxide films through a kinetic response analysis approach

Kamble, Vinayak B and Umarji, Arun M (2015) Effect of Pt doping on the gas sensing properties of porous chromium oxide films through a kinetic response analysis approach. In: RSC ADVANCES, 5 (35). pp. 27509-27516.

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Abstract

The effect of doping trace amounts of noblemetals (Pt) on the gas sensing properties of chromium oxide thin films, is studied. The sensors are fabricated by depositing chromium oxide films on a glass substrate using a modified spray pyrolysis technique and characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The films are porous and nanocrystalline with an average crystallite size of similar to 30 nm. The typical p-type conductivity arises due to the presence of Cr vacancies, formed as a result of Cr non-stoichiometry, which is found to vary upon Pt doping. In order to analyze the effect of doping on the gas sensing properties, we have adopted a kinetic response analysis approach, which is based on Langmuir Adsorption isotherm (LA) theory. The sensor response is analyzed with equations obtained from LA theory and time constants as well as energies of adsorption-desorption are evaluated. It is seen that, Pt doping lowers the Schottky barrier height of the metal oxide semiconductor sensor from 222 meV to 172 meV. Subsequently the reduction in adsorption and desorption energies led to enhancement in sensor response and improvement in the kinetics of the sensor response i.e. the response time as well as recovery times of the sensor.

Item Type:	Journal Article
Publication:	RSC ADVANCES
Publisher:	ROYAL SOC CHEMISTRY
Additional Information:	Copy right for this article belongs to the ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Keywords:	METAL-OXIDES; THIN-FILMS; SENSORS; SNO2; NANOPARTICLES; SENSITIVITY
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	24 Apr 2015 06:20
Last Modified:	24 Apr 2015 06:20
URI:	http://eprints.iisc.ac.in/id/eprint/51407

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