Tunable nanostructured columnar growth of SnO₂ for efficient detection of CO gas

The present work is focused on the growth and modification of the columnar nanostructures of SnO₂ using a glancing angle deposition (GLAD) assisted rf sputtering technique for low temperature detection of carbon monoxide (CO) gas. The GLAD angle and deposition pressure are optimized to tailor the grow of columnar nanostructures of SnO₂, which exhibit an enhanced gas sensing response of 1.50 × 10² towards 500 ppm of CO gas at a comparatively lower operating temperature of 110 °C. The enhanced sensing response at low operating temperature is related to the growth of nanoporous columnar structures of SnO₂ thin film under the GLAD configuration, which results in an enhanced interaction of target CO gas molecules with the large surface area of sensing SnO₂ thin film. The origin of the sensing mechanism supporting the observed response characteristics towards CO gas is identified and discussed in detail.