Study of Metal Oxide (ZnO) Nanostructure based Chemical Sensor

Abstract

Since the beginning of the technology era, sensors have been used in medical diagnosis,
space, industry etc. The recent years have witnessed a demand of low-cost, portable, low-power consumption sensors which do not emphasize space. Technological advances have allowed sensors based on MEMS technology. Extensive research on metal oxide (ZnO) based resistive sensors is beingdone for sensor applications due to its semi-conducting nature, wide band gap, low cost, easyfabrication process.The operation of sensors at room temperature is in increasing demand asit can be operated easily. Yet, operation at low temperatures doesn’t give proper response forthe material to be sensed. Hence, the sensing activities can be enhanced by increasing thesurface of the material, and reducing the size which enhances electrical, physical andmagnetic properties. This work is based on synthesis of zinc-oxide nanowires for Hydrogenand Ethanol sensing at room temperature. Seed layer was deposited on the Silicon substratefor growth of ZnO nanowires were grown at different temperatures and theirmorphologies were observed. Electrical contacts were made by Ag particles. Hydrogen andEthanol sensing was done and their I-V and I-T characteristics were plotted respectively. Maximum sensitivity was found for ZnO NW grown at 85?C with a good response time of 11.42 seconds. Ethanol sensing by ZnO NWs grown at 90?C was found to have maximum sensitivity with a response time less than 41.19 seconds. Thus the above result gives future scope to a develop a real time efficient gas sensor.