Morphology evolution of ZnO thin films from aqueous solutions and their application to liquefied petroleum gas (LPG) sensor

The chemical bath deposition method is used to prepare two-dimensional flakes and one-dimensional rods of ZnO. By changing the bath temperature, ZnO morphology can be changed from flakes to rods. Further orientation of ZnO rods are selectively controlled by varying the content of H2O2 in the bath solution. These films are structurally and morphologically characterized using X-ray diffraction and scanning electron microscopy respectively. The dependence of liquefied petroleum gas (LPG) sensing properties on morphology and orientation of ZnO thin film are investigated. The vertically aligned ZnO rods exhibited the maximum gas response of 49% at 573 K upon exposure to 5200 ppm of LPG.

► Morphology evolution of ZnO structures by chemical method.
► The crystallite orientation strongly affected by content of H2O2 in the bath solution.
► LPG sensing properties of ZnO are explained and well correlated with its morphology.
► Effect of crystallite orientation of ZnO rods on sensing properties are studied and reported.
► Vertically aligned ZnO rods shows improved LPG sensing properties than entangled ones.