Hydrothermal temperature effect on the growth of h-MoO3 thin films using seed layers and their photoluminescence properties

Abstract

In this work, thin films of molybdenum trioxide were successfully deposited via the facile and cost-effective hydrothermal technique. The films were grown at different temperatures of 50, 80, 110, and 130 °C on glass substrates. The growth temperature effects on the optical, morphological, and structural properties of samples were studied. X-ray diffraction (XRD) pattern analysis and Raman spectroscopy revealed that all deposited MoO3 thin films were crystallized in a hexagonal crystal structure. Field emission scanning electron microscope (FESEM) images exhibited that MoO3 thin films were coated by well-shaped hexagonal micro-rods. Also, the diameter of the micro-rods was decreased from 8.95 to 3.60 μm by increasing the hydrothermal growth temperature. At 130 °C, micro-rods were accumulated in the form of micro-flowers. By increasing the growth temperature, the estimated optical bandgap of films was increased from 2.94 to 3.04 eV, respectively. All h-MoO3 fabricated thin films showed photoluminescence (PL) emission at room temperature, and increasing the growth temperature caused the enhancement of the PL intensity. This study provides a simple and low-cost synthesis route at low temperatures to deposit h-MoO3 films for further investigations as in gas sensing and optoelectronic applications.