Study of Structural , Optical and Electrical Properties for Cr -Doped Tio2 Sensor for NH3 Gas

Abstract

Titanium doxide (TiO2) thin films were deposited on quartz substrates by spray pyrolysis method using titanium tetrachloride as precursor solution. Thin films were deposited at temperature substrate 350 ◦C and annealed at 550 ◦C in air for 120 min. Polycrystalline thin films with anatas crystal structure, as evidenced from X-ray diffraction pattern. Optical study shows the optical band gap has been increased with increasing of dopant. Electrical properties have been studied by means of electrical resistivity and Hall measurement. The sensitivity of TiO2: 5% Cr to NH3 gas with concentration 5ppm at room temperature has been modified to (93) % as compared with a pure TiO2.