Structural study and sensitivity measurements of ZnO based ammonia (NH3) sensor

Abstract

Zinc Oxide (ZnO) thin films were prepared on thermally oxidized SiO2 by radio frequency (RF) magnetron sputtering at various substrate temperature ranging from room temperature (25°C) to 500°C. The surface morphology and crystallinity were analyzed by field emission scanning electron microscopy (FESEM) and X-Ray Diffractometer (XRD) respectively. The grain size measured by FESEM is increasing with the increased of substrate temperature used. All films grown were c-axis oriented and the film deposited at 300°C exhibit the highest crystallinity. The film deposited at room temperature exhibit the highest sensitivity due the smallest grain size and the highest surface to volume ratio.