Characterization and gas sensitivity of cadmium oxide thin films prepared by thermal evaporation technique

Abstract Cadmium oxide CdO thin films were deposited by thermal evaporation technique at different substrate temperatures on glass substrates. The XRD analysis shows that CdO films are amorphous and transform to polycrystalline with cubic structure when deposited at 448K and annealed at 573K. The direct energy band gap of CdO thin film decreases with increases of substrate temperature, while at an annealing temperature of 573K the energy gap increases. The results were explained on the biases of structural disordered intruding by the effect of Ts. Other optical constants, such as refractive index, extinction coefficient, dielectric constant were also studied. The response of the films to sense H2 gas has been investigated and they exhibited a maximum sensitivity of 6%. The response time to immediate injection and removal of a certain amount of gas were measured

FABRICAT & STUDY CU0.5IN0.5S2 THIN FILMS COMPOSITE PREPARED BYPYLORYSIS SPRAY METHOD.

Thin film of Cu0.5In0.5S2 has been prepared by spray pyrolysis on different substrate of silicon and glass slides (25mm ×25mm) substrate at temperature (Ts) of 300 ±10oC . The thickness of thin films is 500 ±20nm. The morphology of the prepared film showed asmooth formationwith small grain sizes overall the entire surface.This indicates that the formation of crystalline compounds. The optical characteristics of thin film have been investigated by UV-VIS spectrophotometer in the wavelength range (300 -1000nm ) . The film has a direct allows electronic transition with the optical energy gap ( Eg ) of 2.9 eV . The broadening of the band gap energy occurs with the decrease in the crystallite size. The papered film revealed a good light trapping of wide wavelength spectrum. This means the film is promising in optoelectronic applications. The electrical properties were investigated using Hall measurements techniques; the result provides an evidence of p-type