Gas Sensing and Structural Properties of a Nano-structure MoO3-based Hydrogen Sensor

In this research, thin films of molybdenum trioxide were deposited on a glass substrate using Doctor Blade method. Ammonium Heptamolbudate tetrahydrate (NH4)6Mo7O24 powder is considered as a precursor to this study. Growth of the samples in three main directions of (020), (040) and (060) showed the formation of a layered structure and also the formation of α-phase of molybdenum oxide. In addition, scanning electron microscope imaging of the samples showed flat micro-capsule like structure. Furthermore, gas sensing properties of the fabricated structure were studied in expose to different concentrations of hydrogen gas. The highest and lowest sensitivities were reported about 16 and 91%, for 100 and 1000 ppm of hydrogen gas, respectively, which shows more sensitivity compare to previous studies. Moreover, the fabricated sensor exhibits good stability as well as repeatability for H2 gas detection.