Nanocrystalline CuO Thin Films for H2S Monitoring: Microstructural and Optoelectronic Characterization

Nanocrystalline copper oxide (CuO) thin films were deposited onto glass substrates by a spin coating technique using an aqueous solution of copper acetate. These films were characterized for their structural, morphological, optoelectronic properties by means of X-ray diffraction (XRD) scanning electron microscopy (SEM), UVspectroscopy and four probe method. The CuO films are oriented along (1 1 1) plane with the monoclinic crystal structure. These films were utilized in H2S sensors. The dependence of the H2S response on the operating temperature, H2S concentration of CuO film (annealed at 700 ̊C) was investigated. The CuO film showed selectivity for H2S. The maximum H2S response of 25.2% for the CuO film at gas concentration of 100 ppm at operating temperature 200 ̊C was achieved.