Synthesis and characterization of Cu1-xZnxO composite thin films for sensor application

Cu1-xZnxO composite thin films were prepared using industrially applicable spray pyrolysis technique for volatile organic compound (VOCs) sensor application. Sensing properties for different concentration of VOCs such as acetone, ethanol and methanol were studied at different sensor operating temperature. XRD studies on prepared thin films confirmed formation of CuO-ZnO composite thin films with presence of different peaks for monoclinic structured CuO and hexagonal structure ZnO, it was also observed that formation of composite material improves sensing property towards VOCs. Granular morphology observed from SEM images were also contributed to enhance sensitivity of Cu1-xZnxO thin films. Hot probe experiment reveals that all the thin films were p-type in conductivity nature. Maximum electrical conductivity was achieved for Cu0.75Zn0.25O composite thin films, which also showed highest sensing property for VOCs. Cu0.75Zn0.25O thin films were selective towards ethanol and were capable of detecting 1 ppm of ethanol at operating temperature of 290 degrees C.