Design and fabrication of humidity sensor based on the growth of micro/nano rods of ZnO on the tapered optical fiber

Document Type : Full length research Paper

Abstract

In this paper not expensive and sensitive humidity optical sensor was fabricated based on the growth of nano and micro rods of ZnO on the optical fiber through hydrothermal method. If fiber optic sensors that work based on evanescent waves covered with nanostructures would significantly enhance the sensitivity of sensros. Nano and micro rods of ZnO was formed densly and uniformly on the optical fiber. With exserting the humidity the refractive index around the fiber will change which leads to the variation of the external light intensity. Variations of light intensity which corresponds to the humidity concentration were recorded by spectrophotometer. Response time and recover time of sensor were measured and demonstrated that the ability of sensing humidity in acceptable level (10%-100%). Also the effect of two differet light source (laser He-Ne and white LED) on the sensitivity of sensors were investigated. The structure and morphology of ZnO nano rods were studied through XRD and SEM analysis.

Keywords

Main Subjects


[1] P.H. Yeh, Z. Li, Z.L. Wang, Schottky-gated probe-free ZnO nanowire biosensor, Advanced Materials 21 (2009) 4975–4978.
 [2] B. Weintraub, Y.G. Wei, Z.L. Wang, Optical fiber/ nanowire hybrid structures for efficient three-dimensional dye-sensitized solar cells, Angew. Chemie International Edition 48 (2009) 8981–8985.
[3] J. Anderson, J. chris, G Van de Walle, Fundamentals of zinc oxide as a semiconductor, Reports on Progress in Physics 72 (2009) 29
[4] R.A. Laudise, A.A. Ballman, Hydrothermal synthesis of zinc oxide and zinc sulfide, The Journal of Physical Chemistry64 (1960) 688–691.
[5] B.D. Yao, Y.F. Chan, N. Wang, Formation of ZnO nanostructures by a simple way of thermal evaporation, Applied Physics Letters 81 (2002) 757–759.
[6] H. Yuan, Y. Zhang, Preparation of well-aligned ZnO whiskers on glass substrate by atmospheric MOCVD, Journal of Crystal Growth 263 (2004) 119–124.
[7] Y.W. Heo, V. Varadarajan, M. Kaufman, K. Kim, D. P.  Norton, F. Ren, P. H. Fleming, Site-specific growth of ZnO nanorods using catalysis-driven molecular-beam epitaxy, Applied Physics Letters 81 (2001) 3046–3048.
[8] Y. Sun, G.M. Fuge, M.N.R. Ashfold, Growth of aligned ZnO nanorod arrays by catalyst-free pulsed laser deposition methods, Chemical Physics Letters 396 (2004), 21–26.
[9] W.T. Chiou, W.Y. Wu, J.M. Ting, Growth of single crystal ZnO nanowires using sputter deposition, Diamond and Related Materials 12 (2003), 1841–1844.
[10] K. Govender, D.S. Boyle, P.B. Kenway, P. O'Brien, Understanding the factors that govern the deposition and morphology of thin films of ZnO from aqueous solution, Journal of Materials Chemistry 14 (2004) 2575–2591.
[11] W. James, R. Tatam, Fiber optic sensors with nano-structured coatings, Journal of Optics A 8 (2006)
[12] L. Yanjuan, Growth of well-arrayed ZnO nanorods on thinned silic fiber and application for humidity sensing, Optical Society of America 20 (2012).
[13] M. Konstantaki, An ethanol vapor detection probe based on a ZnO nanorod coated optical fiber LPG, Optics Express 20 (2012) 19404-1941.
[14] M. Batumalay, Z. Harith, H.A. Rafaie, F. Ahmad, M. Khasanah, S. W. Harun, R. M. Nor, and H. Ahmad, Tapered plastic optical fiber coated with ZnO nanostructures for the measurement of uric acid concentrations and changes in relative humidity, Sensors and Actuators A Physical 210 (2014) 190-196.
[15] B. Sunandan, D. Joydeep, Effect of seeded substrates on hydrothermally grown ZnO nanorods, Journal of Sol-Gel Technology 50 (2009) 456-464.
[16] B. Sunandan, D. Joydeep, Hydrothermal growth of ZnO nanostructures, Science and Technology of Advanced Materials 10 (2009)
[17] L.N. Demianets, D.V. Kostomarov, Mechanism of zinc oxide single crystal growth under hydrothermal conditions, Annales de Chimie Science des Matériaux 26 (2001) 193-198.
[18] M.N.R. Ashfold, R.P. Doherty, The kinetics of the hydrothermal growth of ZnO nanostructures, Thin Solid Films 515 (2007) 8679-8683.
[19] J. Bae, M.K. Song, Fiber supercapacitors made of nanowire-fiber hybrid structures for wearable/flexible energy storage, Angewandte Chemie International Edition 50 (2011) 1683-1687.
[20] M. El-Sherif, Lalitkumar Bnansal, Jianming Yuan, Fiber optic sensors for detection of toxic and biological threats, sensors 7 (2007) 3100-3118.
[21] Anna. Og. Dikovska, P.A. Atanasov, A.Ts. Andreev, B.S. Zafirova, E.I. Karakoleva, T.R. Stoyanchov, Zno thin film on the side polished optical fiber for gas sensing applications, Applied surface science 254 (2007) 1087-1090.
[22] T.L. Yeo, T. Sun, K.T.V. Grattan, Fiber-optic sensor technologies for humidity and moisture measurement, Sensors and actuators A 144 (2008) 208-295
[23] Y. Shizhuo, B.R. Paul, T.S. Yu Francis, Fiber optic sensors, CRC Press New York (2008).