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Hydrogen Gas Sensor Based on ZnO Nanoroads Grown on Si by Thermal Evaporation




Author(s)

Hind Ibraheem Abdulgafour¹, Hassan Hadi Darwoysh^{1, 2} and Faez Mohamad Hassan^2*

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DOI:10.17265/2161-6213/2016.3-4.002

1. Departement of Physics, Ministry of Science and Technology, Baghdad, AlKerrada 10069, Iraq
2. Department of Physics, College of Education, Al-Mustansiriya University, Baghdad, New Baghdad 10062, Iraq

High-quality ZnO (Zinc oxide) nanorods grown on Si substrate have been synthesized for hydrogen gas sensor application through a low-cost catalyst-free process by thermal evaporation at 800 ºC. The morphological, structural and optical properties of the ZnO nanorods have been examined. In this study, Pd/ZnO/Pd MSM (Metal-semiconductor-metal) gas sensor has been fabricated based on the ZnO nanorods. The absence of a seed layer and the coalescence of ZnO nanorods were the key factors responsible for the high sensitivity of the gas sensor at room temperature. The sensitivity of ZnO nanorods is measured at different concentrations from 25 ppm to 150 ppm of H2 gas at room temperature. The highest response of the ZnO/Si sensor was 110% in the presence of 500 ppm of H2. This high sensitivity can be attributed to the high surface-area- to-volume ratio of the nanorods between the Pd contacts of the MSM configuration.

ZnO, nanostructures, thermal evaporation, gas sensor.