Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Dec 29;16(1):342.
doi: 10.3390/ma16010342.

ITO Thin Films for Low-Resistance Gas Sensors

Aleksei V Almaev  1   2 , Viktor V Kopyev  1 , Vadim A Novikov  1 , Andrei V Chikiryaka  3 , Nikita N Yakovlev  1 , Abay B Usseinov  4 , Zhakyp T Karipbayev  4 , Abdirash T Akilbekov  4 , Zhanymgul K Koishybayeva  4 , Anatoli I Popov  4   5
Affiliations

ITO Thin Films for Low-Resistance Gas Sensors

Aleksei V Almaev et al. Materials (Basel). .

Abstract

Indium tin oxide thin films were deposited by magnetron sputtering on ceramic aluminum nitride substrates and were annealed at temperatures of 500 °C and 600 °C. The structural, optical, electrically conductive and gas-sensitive properties of indium tin oxide thin films were studied. The possibility of developing sensors with low nominal resistance and relatively high sensitivity to gases was shown. The resistance of indium tin oxide thin films annealed at 500 °C in pure dry air did not exceed 350 Ohms and dropped by about 2 times when increasing the annealing temperature to 100 °C. Indium tin oxide thin films annealed at 500 °C were characterized by high sensitivity to gases. The maximum responses to 2000 ppm hydrogen, 1000 ppm ammonia and 100 ppm nitrogen dioxide for these films were 2.21 arbitrary units, 2.39 arbitrary units and 2.14 arbitrary units at operating temperatures of 400 °C, 350 °C and 350 °C, respectively. These films were characterized by short response and recovery times. The drift of indium tin oxide thin-film gas-sensitive characteristics during cyclic exposure to reducing gases did not exceed 1%. A qualitative model of the sensory effect is proposed.

Keywords: gas sensors; indium tin oxide; thin films.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Microscopic photo of the sensor element based on ITO thin film.
Figure 2
Figure 2
AFM images of the ITO thin-film surfaces annealed at Tann = 500 °C (a) and 600 °C (b).
Figure 3
Figure 3
EDX spectra of ITO thin films annealed at Tann = 500 °C and 600 °C.
Figure 4
Figure 4
XRD spectra of ITO thin films annealed at Tann = 500 °C and 600 °C.
Figure 5
Figure 5
Optical transmission spectra (a) and α2 versus the photon energy (b) for ITO thin films annealed at Tann = 500 °C and 600 °C.
Figure 6
Figure 6
Temperature dependence of the ITO thin-film resistance in pure dry air at Tann = 500 °C and 600 °C.
Figure 7
Figure 7
Temperature dependence of ITO thin-film responses to fixed concentrations of various gases at Tann = 500 °C and 600 °C.
Figure 8
Figure 8
Time dependence of ITO thin-film resistance at Tann = 500 °C (a) and 600 °C (b) when exposed to various gases and T = TMAX.
Figure 9
Figure 9
Temperature dependence of response times for ITO thin films annealed at Tann = 500 °C (a) and 600 °C (b) under exposure to various gases.
Figure 10
Figure 10
Temperature dependence of recovery times for ITO thin films annealed at Tann = 500 °C (a) and 600 °C (b) under exposure to various gases.
Figure 11
Figure 11
Dependence of ITO-500 thin-film responses on concentrations of H2, NH3, CO and NO2 at T = TMAX.
Figure 12
Figure 12
Time dependence of the ITO-500 thin-film resistance under cyclic exposure to H2, NH3, CO and NO2 at T = TMAX.
Figure 13
Figure 13
I–V characteristics of ITO-500 thin films in pure dry air and when exposed to H2, NH3, CO and NO2 at T = TMAX.
See this image and copyright information in PMC

References

    1. Korotcenkov G. Metal oxides for solid-state gas sensors: What determines our choice? Mater. Sci. Eng. B. 2007;139:1–23. doi: 10.1016/j.mseb.2007.01.044. - DOI
    1. Shah V., Bhaliya J., Patel G.M., Joshi P. Room-Temperature Chemiresistive Gas Sensing of SnO2 Nanowires: A Review. J. Inorg. Organomet. Polym. 2022;32:741–772. doi: 10.1007/s10904-021-02198-5. - DOI
    1. Afzal A. β-Ga2O3 nanowires and thin films for metal oxide semiconductor gas sensors: Sensing mechanisms and performance enhancement strategies. J. Mater. 2019;5:542–557. doi: 10.1016/j.jmat.2019.08.003. - DOI
    1. Gu H., Wang Z., Hu Y. Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures. Sensors. 2012;12:5517–5550. doi: 10.3390/s120505517. - DOI - PMC - PubMed
    1. Shi Y., Xu H., Liu T., Zeb S., Nie Y., Zhao Y., Qin C., Jiang X. Advanced development of metal oxide nanomaterials for H2 gas sensing applications. Mater. Adv. 2021;2:1530. doi: 10.1039/D0MA00880J. - DOI

LinkOut - more resources