Annealing Temperature Dependent on Microstructure and Ethanol Gas Sensing Properties of TiO₂Thin Films

Abstract

The TiO2 thin films were prepared by a dc reactive magnetron sputtering technique from high purity Ti target on silicon (100) wafers and alumina substrates inter-digital with gold electrodes. The as-deposited films were annealed from 400°C up to 800°C with 100 °C steps for 1 hour in air ambience in order to promote microstructure, morphology and gas-sensing properties. The change in microstructure and morphology of the films were investigated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The enhancement in the gas-sensing properties was test by ethanol gas. The prepared thin films were exposed to ethanol gas at concentration 1,000 ppm in purify dry air carrier. The resistance was measured as a function of the ethanol concentration of the films at operated temperatures in the range of 250 - 350°C. The influence of annealing temperature at 500 °C of TiO2 thin film has a highest sensitivity at 350 °C operated temperature.