Enhanced performance of the tangerines-like CuO-based gas sensor using ZnO nanowire arrays

In this work, sensors based on the ZnO nanowire arrays/CuO nanospheres heterostructure were prepared by using the simple low temperature hydrothermal method. X-ray diffraction (XRD), field emission scanning elec-tron microscopy (FESEM), transmission electron microscopy (HRTEM) and energy dispersive spectrometry (EDX) were used to characterize the crystal phase, structure and surface morphology of the as-prepared samples, respectively. The sensing characteristics of the as prepared samples were systematically measured. Obviously, the sensors based on the ZnO/CuO heterostructure exhibited excellent sensor parameters than pure CuO nano -spheres. The response value of the ZnO/CuO heterostructure sensor with the growth time of 5 h (ZC-2) to 100 ppm of ethanol gas is up to 55.4 at 122 degrees C, which is about 8.8 fold and 3.4 fold more than that of pure CuO nanospheres (R = 6.3) and ZnO nanowire arrays (R = 16.4), respectively. In addition, the ZC-2 sensor exhibits the excellent selectivity for ethanol compared to other test gases. Significant improvement of the gas sensing characteristics was related to the formation of n-p heterojunction. The prepared ZC-2 gas sensor exhibits broad application prospects in the detection of ethanol.