STRATEGIES FOR IMPROVING THE RECOVERY TIME OF SEMICONDUCTOR METAL-OXIDE GAS SENSORS
Keywords:
Keywords: metal-oxide semiconductor; gas sensor; recovery time; desorption energy; gas diffusion; catalytic spillover; light activation; temperature modulation.Abstract
Abstract. The recovery time is, together with sensitivity and selectivity, one of
the decisive figures of merit of semiconductor metal-oxide (SMOx) chemiresistors, yet
it is frequently the slowest and least optimised parameter. A long recovery limits the
duty cycle, prevents continuous real-time monitoring and increases the energy budget
of a sensor node. This paper analyses the physical origin of the recovery transient and
reviews, within a single quantitative framework, the strategies available to shorten it.
We model the recovery as a desorption-limited first-order relaxation whose time
constant follows an Arrhenius law; from a linearised representation an effective
desorption energy of about 0.62 eV is obtained. We then treat the diffusion-limited
regime in porous layers, identify the cross-over between reaction- and diffusion-
control, and quantify how operating temperature, noble-metal loading, heterojunction
formation, grain-size reduction, light activation and thermal modulation each act on
these two limiting times. The contributions are summarised and design rules are
proposed for sub-second recovery without sacrificing sensitivity.
References
References
1. Dutta T., Noushin T., Tabassum S., Mishra S.K. Road map of semiconductor metal-
oxide-based sensors: A review. Sensors, 2023, vol. 23, no. 15, 6849.
2. Goel N., Kunal K., Kushwaha A., Kumar M. Metal oxide semiconductors for gas
sensing. Engineering Reports, 2023, vol. 5, no. 6, e12604.
3. Liu X., Cheng S., Liu H., Hu S., Zhang D., Ning H. A survey on gas sensing
technology. Sensors, 2012, vol. 12, no. 7, pp. 9635–9665.
4. Barsan N., Weimar U. Conduction model of metal oxide gas sensors. Journal of
Electroceramics, 2001, vol. 7, no. 3, pp. 143–167.
5. Yamazoe N., Sakai G., Shimanoe K. Oxide semiconductor gas sensors. Catalysis
Surveys from Asia, 2003, vol. 7, no. 1, pp. 63–75.
6. Wang X., Wang Y., Tian F., et al. From the surface reaction control to gas-diffusion
control: the synthesis of hierarchical porous SnO₂ microspheres and their gas-
sensing mechanism. Journal of Physical Chemistry C, 2015, vol. 119, no. 27, pp.
15963–15976.
7. Sakai G., Matsunaga N., Shimanoe K., Yamazoe N. Theory of gas-diffusion
controlled sensitivity for thin film semiconductor gas sensor. Sensors and Actuators
B, 2001, vol. 80, no. 2, pp. 125–131.
8. Kolmakov A., Klenov D., Lilach Y., Stemmer S., Moskovits M. Enhanced gas
sensing by individual SnO₂ nanowires and nanobelts functionalized with Pd catalyst
particles. Nano Letters, 2005, vol. 5, no. 4, pp. 667–673.
9. Degler D., Weimar U., Barsan N. Current understanding of the fundamental
mechanisms of doped and loaded semiconducting metal-oxide-based gas sensing
materials. ACS Sensors, 2019, vol. 4, no. 9, pp. 2228–2249.
10. Korotcenkov G. The role of morphology and crystallographic structure of metal
oxides in response of conductometric-type gas sensors. Materials Science and
Engineering: R, 2008, vol. 61, no. 1–6, pp. 1–39.
11. Xu C., Tamaki J., Miura N., Yamazoe N. Grain size effects on gas sensitivity of
porous SnO₂-based elements. Sensors and Actuators B, 1991, vol. 3, no. 2, pp. 147–
155.
12. Comini E., Cristalli A., Faglia G., Sberveglieri G. Light enhanced gas sensing
properties of indium oxide and tin dioxide sensors. Sensors and Actuators B, 2000,
vol. 65, no. 1–3, pp. 260–263.
13. Chinh N.D., Quang N.D., Lee H., et al. NO gas sensing kinetics at room
temperature under UV light irradiation of In₂O₃ nanostructures. Scientific Reports,
2016, vol. 6, 35066.
14. Lee A.P., Reedy B.J. Temperature modulation in semiconductor gas sensing.
Sensors and Actuators B, 1999, vol. 60, no. 1, pp. 35–42.
15. Majhi S.M., Mirzaei A., Kim H.W., Kim S.S., Kim T.W. Recent advances in
energy-saving chemiresistive gas sensors: A review. Nano Energy, 2021, vol. 79,
105369.
16. Tiemann M. Porous metal oxides as gas sensors. Chemistry – A European Journal,
2007, vol. 13, no. 30, pp. 8376–8388.
17. Barsan N., Weimar U. Understanding the fundamental principles of metal oxide
based gas sensors; the example of CO sensing with SnO₂ sensors in the presence of
humidity. Journal of Physics: Condensed Matter, 2003, vol. 15, no. 20, R813.
18. Ji H., Zeng W., Li Y. Gas sensing mechanisms of metal oxide semiconductors: A
focus review. Nanoscale, 2019, vol. 11, no. 47, pp. 22664–22684.
