Catalyst-free growth of Al-doped SnO2 zigzag-nanobelts for low ppm detection of organic vapours

• Pure and Al- SnO2 nanostructures were synthesized for effective sensing of ethanol/acetone.
• The growth morphology and defect structure of the Al-doped SnO2 zigzag nanobelts were analyzed.
• Al-doped SnO2 nanobelt-sensor exhibits excellent ethanol and acetone sensitivity.

In this effort, we report on development of specific sensors dedicated for detection of two of these volatiles, namely ethanol and acetone, below the prescribed statutory limits. Single crystalline Al-doped SnO2 zigzag nanobelt structures were deposited on Si substrate by a catalyst-free thermal evaporation method. The Al-doped SnO2 zigzag nanostructures exhibit high sensitivity and repeatability together with coveted features like fast response and excellent stability. Structural attributes involving the crystal quality and morphology of Al-doped SnO2 zigzag nanobelts were analyzed using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy and transmission electron microscopy. The microscopic images revealed formation of randomly oriented ‘zigzag-like’ nanobelts with characteristic width between 60 nm and 200 nm and length of 50–300 µm. The Al-doping was observed to have a discerning effect in enhancing the sensitivity in comparison to the pristine nanowires by creating excess oxygen vacancies in the crystal lattice, confirmed through XPS and PL spectra.