Catalyst free vapor–solid deposition of morphologically different b-Ga2O3 nanostructure thin films for selective CO gas sensors at low temperature

Anal. Methods, 2016, volume 8, issue 15, pages 3224-3235, The Royal Society of Chemistry

Schematic diagrams for the change in sensor resistance upon exposure to air and reduction gas (CO) in the case of n-type b-Ga2O3 nanostructure sensing films.

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Writers: Girija, K. and Thirumalairajan, S. and Mastelaro, Valmor R. and Mangalaraj, D.

Keywords: Gas; Sensor; X-ray; nanostructures

Abstract: In the present work{,} we have demonstrated the deposition of novel morphologically different [small beta]-Ga2O3 nanostructure (rod and rectangular shape) thin films prepared by a vapour solid mechanism using a temperature controllable horizontal tubular furnace without using any metal catalyst or additives. The effects of growth parameter{,} surface morphology and particle size on the [small beta]-Ga2O3 thin films were systematically investigated using electron micrograph images. X-ray diffraction patterns of the prepared films reveal preferential orientation along the (111) plane. In addition{,} studies of the toxic carbon monoxide (CO) gas sensing performance show that the as-prepared rod shaped [small beta]-Ga2O3 nanostructures show good sensitivity{,} short response and recovery time (49-40 s) upon exposure to CO gas at 100 [degree]C in comparison with rectangular shape [small beta]-Ga2O3 (56-63 s). Through exploring the gas sensing mechanism{,} it is argued that the sensor performance dramatically improves due to the high surface area{,} particle size{,} shape{,} numerous surface active sites and the oxygen vacancies. The developed 1D [small beta]-Ga2O3 thin films not only possess unique shape and size{,} but also influence the development of various potential applications.

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