Gas Sensing and Structural Properties of a Nano-structure MoO3-based Hydrogen Sensor

Document Type : Original Article


1 Department of Electrical Engineering and Robotic, Shahrood University of Technology, shahrood, Iran

2 Department of Physics, Shahrood University of Technology, shahrood, Iran


In this research, thin films of molybdenum trioxide were deposited on a glass substrate using Doctor Blade method. Ammonium Heptamolbudate tetrahydrate (NH4)6Mo7O24 powder is considered as a precursor to this study. Growth of the samples in three main directions of (020), (040) and (060) showed the formation of a layered structure and also the formation of α-phase of molybdenum oxide. In addition, scanning electron microscope imaging of the samples showed flat micro-capsule like structure. Furthermore, gas sensing properties of the fabricated structure were studied in expose to different concentrations of hydrogen gas. The highest and lowest sensitivities were reported about 16 and 91%, for 100 and 1000 ppm of hydrogen gas, respectively, which shows more sensitivity compare to previous studies. Moreover, the fabricated sensor exhibits good stability as well as repeatability for H2 gas detection.


1.     Eranna, G., 2016. Metal oxide nanostructures as gas sensing devices. CRC press.
2.     Eranna, G., Joshi, B.C., Runthala, D.P. and Gupta, R.P., 2004. Oxide materials for development of integrated gas sensors—a comprehensive review. Critical Reviews in Solid State and Materials Sciences29(3-4), pp.111-188.
3.     Tricoli, A., Righettoni, M. and Teleki, A., 2010. Semiconductor gas sensors: dry synthesis and application. Angewandte Chemie International Edition49(42), pp.7632-7659.
4.     Zhang, J., Qin, Z., Zeng, D. and Xie, C., 2017. Metal-oxide-semiconductor based gas sensors: screening, preparation, and integration. Physical Chemistry Chemical Physics19(9), pp.6313-6329.
5.     Rahmani, M.B., Keshmiri, S.H., Yu, J., Sadek, A.Z., Al-Mashat, L., Moafi, A., Latham, K., Li, Y.X., Wlodarski, W. and Kalantar-Zadeh, K., 2010. Gas sensing properties of thermally evaporated lamellar MoO3Sensors and Actuators B: Chemical145(1), pp.13-19.
6.     Kröger, M., Hamwi, S., Meyer, J., Riedl, T., Kowalsky, W. and Kahn, A., 2009. P-type doping of organic wide band gap materials by transition metal oxides: A case-study on Molybdenum trioxide. Organic Electronics10(5), pp.932-938.
7.     Mousavi-Zadeh, S.H. and Rahmani, M.B., 2018. Synthesis and ethanol sensing characteristics of nanostructured MoO3: Zn thin films. Surface Review and Letters25(01), pp.1-10.
8.     Dhara, A., Hodes, G. and Sarkar, S.K., 2014. Two stage chemical bath deposition of MoO3 nanorod films. RSC Advances4(96), pp.53694-53700.
9.     Davtyan, D., Manukyan, K., Mnatsakanyan, R. and Kharatyan, S., 2010. Reduction of MoO3 by Zn: Reducer migration phenomena. International Journal of Refractory Metals and Hard Materials28(5), pp.601-604.
10.   Rahmani, M.B., Keshmiri, S.H., Shafiei, M., Latham, K., Wlodarski, W., Du Plessis, J. and Kalantar-Zadeh, K., 2009. Transition from n-to p-type of spray pyrolysis deposited Cu doped ZnO thin films for NO2 sensing. Sensor Letters7(4), pp.621-628.
11.   Breedon, M., Rahmani, M.B., Keshmiri, S.H., Wlodarski, W. and Kalantar-zadeh, K., 2010. Aqueous synthesis of interconnected ZnO nanowires using spray pyrolysis deposited seed layers. Materials Letters64(3), pp.291-294.
12.   Hübert, T., Boon-Brett, L., Black, G. and Banach, U., 2011. Hydrogen sensors–a review. Sensors and Actuators B: Chemical157(2), pp.329-352.
13.   Cai, L., McClellan, C.J., Koh, A.L., Li, H., Yalon, E., Pop, E. and Zheng, X., 2017. Rapid flame synthesis of atomically thin MoO3 down to monolayer thickness for effective hole doping of WSe2Nano letters17(6), pp.3854-3861.
14.   Jadkar, V., Pawbake, A., Waykar, R., Jadhavar, A., Mayabadi, A., Date, A., Late, D., Pathan, H., Gosavi, S. and Jadkar, S., 2017. Synthesis of orthorhombic-molybdenum trioxide (α-MoO3) thin films by hot wire-CVD and investigations of its humidity sensing properties. Journal of Materials Science: Materials in Electronics28(21), pp.15790-15796.
15.   Li, T., Zeng, W., Zhang, Y. and Hussain, S., 2015. Nanobelt-assembled nest-like MoO3 hierarchical structure: Hydrothermal synthesis and gas-sensing properties. Materials Letters160, pp.476-479.
16.   Sun, Y.F., Liu, S.B., Meng, F.L., Liu, J.Y., Jin, Z., Kong, L.T. and Liu, J.H., 2012. Metal oxide nanostructures and their gas sensing properties: a review. Sensors, 12(3), pp.2610-2631.
17.   Wang, C., Yin, L., Zhang, L., Xiang, D. and Gao, R., 2010. Metal oxide gas sensors: sensitivity and influencing factors. Sensors, 10(3), pp.2088-2106.
18.   Vinoth, E., Gowrishankar, S. and Gopalakrishnan, N., 2018. Effect of Mg doping in the gas-sensing performance of RF-sputtered ZnO thin films. Applied Physics A: Materials Science & Processing124(433), pp.1-8.
19.   Kwon, H., Lee, Y., Hwang, S. and Kim, J.K., 2017. Highly-sensitive H2 sensor operating at room temperature using Pt/TiO2 nanoscale Schottky contacts. Sensors and Actuators B: Chemical241, pp.985-992.
20.   Alsaif, M.M., Balendhran, S., Field, M.R., Latham, K., Wlodarski, W., Ou, J.Z. and Kalantar-Zadeh, K., 2014. Two dimensional α-MoO3 nanoflakes obtained using solvent-assisted grinding and sonication method: application for H2 gas sensing. Sensors and Actuators B: Chemical192, pp.196-204.