tailieunhanh - Study the response of gas sensor usin Zno nanorods synthesized by hydrothermal method

Low-dimensional nano structures ZnO are potential material for optoelectronicand gassensing applications. The syntheses of a large quantity of ZnO nanostructures play an important role for practical applications for future. In the paper, we propose hydrothermal reduction method to synthesize large quantities ZnO nanorods under atmospheric pressure and without using any catalysts. As-prepared ZnO nanorods exhibited a hexagonal wurtzite crystal structure. | Journal of Science and Technology 54 (5A) (2016) 201-207 STUDY THE RESPONSE OF GAS SENSOR USING ZnO NANORODS SYNTHESIZED BY HYDROTHERMAL METHOD Hoang Van Han*, Chu Van Tuan, Trần Trung Hung Yen University of Technology and Education, Dan Tien - Khoai Chau - Hung Yen * Email: hoangvhan@ Received: 15 July 2016; Accepted for publication: 4 December 2016 ABSTRACT Low-dimensional nano structures ZnO are potential material for optoelectronicand gassensing applications. The syntheses of a large quantity of ZnO nanostructures play an important role for practical applications for future. In the paper, we propose hydrothermal reduction method to synthesize large quantities ZnO nanorods under atmospheric pressure and without using any catalysts. As-prepared ZnO nanorods exhibited a hexagonal wurtzite crystal structure. For sensing properties, ZnO nanorods were coated on the Pt interdigitated microelectrodes arrays and examined at operating temperatures of 200 to 350 oC for the detection capacity of NO2 gas. The changes in response resistance revealed that the sensor exhibited a high sensing performance for low concentrations of NO2 gas ( ppm). Additionally, the ZnO nanowires sensors have a good performance to ethanol. Keywords: ZnO, nanorods, gas sensor. 1. INTRODUCTION In recent years, Zinc oxide (ZnO) is one of the first materials studied as a gas sensor [1 – 3]. This is primarily due to the high mobility of conduction electrons in the material and good chemical and thermal stability under operating conditions [4]. It is a direct band gap wurtzite type semiconductor with band gap energy of eV at room temperature, and a very large exciton binding energy of about 60 meV. ZnO presents interesting electrical, optical, acoustic and chemical properties, which find wide applications in acoustic and short wavelength optical devices. Although ZnO is one of the earliest materials developed as a gas sensing material, because of high operating temperature (around .