ITO/ Si gas sensor was fabricated by an efficient and size – controlled by using
DC-Sputtering technique suitable for large deposition area and high quality thin
films. Structural, optical and electrical properties of ITO thin films were investigated
and analyzed extensively under different doping concentration. Structure and surface
morphology of ITO thin films were characterized by X-ray diffraction, Atomic Force
Microscope. XRD technique that showed these films is polycrystalline structure with
a preferred orientation of (222),( 440),(400) the best orientation plain is (222) It was
found that crystalline size decreases with increasing doping concentration. The
optical properties of ITO thin films were studied such as transmissions, energy gap
The transmittance was measured in the wavelength range from(300nm to 900 nm) for
all the films it was highly transparent (greater than 85%). The optical energy band
gap was increased with doping concentration in range from (3.9 to 4.15) eV. The
electrical properties for ITO thin films include D.C electrical conductivity and Hall
effect which shows that the type of films is (n- type), and the film has two activation
energies in the rang (305-355)K, and the resistivity increases with doping
concentration at 8wt%. The sensitivity toward NH3, NO2 gas has been measured.In2O3
doped with (Sn) has higher sensitivity to NH3, The sensitivity toward, NO2 gas has
been measured, where In2O3 doped with (Sn) has higher sensitivity to NO2than to
NH3.
Keywords: D.C Sputtering, ITO, Gas sensor
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