Open Access Open Access  Restricted Access Subscription or Fee Access

Analytical Study on Humidity Sensing of Nanostructured Tin Oxide

Vivek Kumar, Manoj Kumar, Dayal C. Sati, Parveen kumar


Nanocrystalline tin oxide powder was prepared by a mechanochemical method. The synthesised powder was characterised using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD shows the crystalline nature of the synthesised material. The crystallite size was estimated using Debye–Scherrer equation and its minimum value was 9 nm. Surface morphologies of the sensing pellets were investigated using SEM. Pellets as well as thick films were used as sensing elements for humidity sensing measurement. Thick film was prepared on alumina substrate using screen printing technique. Solid-state pellets as well as films were subjected to humidity-sensing measurements in a specially designed humidity chamber. Variations in resistance with relative humidity (%RH) were measured. The effects of annealing on the surface morphologies as well as on the sensitivity of the sensor were also investigated. Hysteresis and ageing effects on experimental results were found 60% and 64%, respectively, for the sensing element prepared after annealing at 600°C.


Nanocrystalline SnO2, mechanochemical method, surface morphology, humidity sensor

Full Text:



G.A. Ozin, Nanochemistry-synthesis in diminishing dimensions, Adv. Mater. 4 (1992), pp. 612–649.

S. Shukla, L. Ludwig, C. Parrish, and S. Seal, Inverse catalyst effect observed for nanocrystalline-doped tin oxide sensor at lower operating temperatures, Sens. Actuators B 104 (2005), pp. 223–231.

C. Xu, J. Tamaki, N. Miura, and N. Yamazoe, Grain size effects on gas sensitivity of porous SnO2 based elements, Sens. Actuators B 3 (1991), pp. 147–155.

G. Zhang and M. Liu, Effect of particle size and dopant on properties of SnO2 based gas sensors, Sens. Actuators B 69 (2000), pp. 144–152.

J. Gong, Q. Chen, M.-R. Lian, N.-C. Liu, R.G. Stevenson, and F. Adami, Michromachined nanocrystalline silver doped SnO2 H2S Sensor, Sens. Actuators B 114 (2006), pp. 32–39.

J.R. Brown, P.W. Haycock, L.M. Smith, A.C. Jones, and E.W. Williams, Response behavior of tin oxide thin film gas sensors grown by MOCVD, Sens. Actuators B 63 (2000), pp. 109–114.

Y. Wu, M. Tong, X. He, Y. Zhang, and G. Dai, Thin film sensors of SnO2-CuO-SnO2 sandwich structure to H2S, Sens. Actuators B 79 (2001), pp. 187–191.

J. Tamaki, K. Shimanoe, Y. Yamada, Y. Yamamoto, N. Miura, and N. Yamazoe, Dilute hydrogen sulfide sensing properties of CuO-SnO2 thin film prepared by low pressure evaporation method, Sens. Actuators B 49 (1998), pp. 121–125.

V.R. Katti, A.K. Debnath, K.P. Muthe, M. Kaur, A.K. Dua, S.C. Gadkari, S.K. Gupta, and V.C. Sahni, Mechanism of drifts in H2S sensing properties of SnO2-CuO composite thin film sensors prepared by thermal evaporation, Sens. Actuators B 96 (2003), pp. 245–252.

R.B. Vasiliev, M.N. Rumyantseva, N.V. Yakovlev, and A.M. Gaskov, CuO/SnO2 thin film heterostructures as chemical sensors to H2S, Sens. Actuators B 50 (1998), pp. 186–193.

J. Li, Y. Wan, X. Gao, Q. Ma, L. Wang, and J. Ha, H2S sensing properties of the SnO2-based thin films, Sens. Actuators B 65 (2000), pp. 111–113.

A. Chowdhuri, V. Gupta, and K. Sreenivas, Enhanced catalytic activity of ultrathin CuO islands on SnO2 films for fast response H2S gas sensors, IEEE sensor J. 3 (2003), pp. 680–686.

P.-G. Su, Y.-L. Sun, and C.-C. Lin, Humidity sensor based on PMMA simultaneously doped with two different salts, Sens. Actuators B 113 (2006), pp. 883–886.

S. Agarwal and G.L. Sharma, Humidity sensing properties of (Ba, Sr) TiO3 thin films grown by hydrothermal- electrochemical method, Sens. Actuators B 85 (2002), pp. 205–211.

G. Sberveglieri, R. Murri, and N. Pinto, Characterisation of porous Al2O3-SiO2/Si sensor for low and medium humidity ranges, Sens. Actuators B 23 (1995), pp. 177–180.

J. Holc, J. Sluenocko, and M. Hrovat, Temperature characteristics of electrical properties of (Ba, Sr) TiO3 thick film humidity sensors, Sens. Actuators B 26–27 (1995), pp. 99–102.

M.E.V. Costa, P.Q. Mantas, and J.L. Baptista, Effect of electrode alternations on the a.c. behavior of the LiO2-ZnO humidity sensors, Sens. Actuators B 26–27 (1995), pp. 312–314.

E. Traversa, Ceramic sensors for humidity detection: The state-of-art and future developments, Sens. Actuators B 23 (1995), pp. 135–156.

M. Bahyan, T. Hashmi, and A.W. Brinkman, Sintering and humidity sensitive behavior of the ZnCr2O4-K2Cr2O4 ceramic system, J. Mater. Sci. 32 (1997), pp. 6619–6623.

Y.C. Yeh, T.Y. Tseng, and D.A. Cheng, Electrical properties of TiO2 porous ceramic humidity sensors, J. Am. Ceram. Soc. 73 (1990), pp. 1992–1998.

L. Wu, C.C. Wu, and M.M. Wu, Humidity sensitive SrO2 ceramics, J. Electron Mater. 19 (1990), pp. 197–200.

T. Nitta, Z. Terrada, and S. Hayakawa, Humidity sensitive electrical conduction of MgCr2O4-TiO2 porous ceramics, J. Am. Ceram. Soc. 63 (1987), pp. 295–300.

B. Chachulski and J. Gebicki, Properties of a polyethyleamine based sensor for measuring medium and high relative humidity, Meas. Sci. Technol. 17 (2006), pp. 12–16.

T. Seiyama and Kodansha, Development and applications of ceramic humidity sensors, Chem. Sens. Technol. 1 (1998), pp. 57–78.

T. Nitta, Z. Terrada, and S. Hayakawa, Humidity-sensitive electrical conduction of MgCr2O4-TiO2 porous ceramics, J. Am. Ceram. Soc. 63 (1980), pp. 295–300.

T. Nitta, J. Terada, and F. Fukushima, Multifunctional ceramic sensors: Humidity-gas sensor and temperature- humidity sensor, IEEE Trans. Electron Devices ED-29 (1982), pp. 95–101.

J.H. Anderson and G.A. Parks, The electrical conductivity of silica gel in the presence of adsorbed water, J. Phys. Chem. 72 (1968), pp. 3362–3368.


  • There are currently no refbacks.