Low-pressure thermal chemical vapour deposition of molybdenum oxide nanorods

Molybdenum oxide nanorods were synthesized on different substrates in the thermal chemical vapour deposition system at low pressure, where the molybdenum trioxide and selenium powders were used as the source materials. The results of field emission scanning electron microscope, transmission electron microscope, X-ray diffractometer, energy dispersive X-ray spectrometer and micro-Raman spectroscope indicate that the molybdenum oxide nanorods have a single-crystalline structure and are mainly composed of MoO₃ with traces of MoO₂ and Mo₄O₁₁. A vapour-solid growth mechanism based on the condensation of MoO_3-x molecules and the diffusion of MoO₃ molecules on the substrate has been proposed to explain the formation of molybdenum oxide nanorods. Furthermore, the photoluminescence (PL) properties of molybdenum oxide nanorods have been studied in Ramalog system using a 325 nm line of He-Cd laser as the excitation source. The PL results show that the molybdenum oxide nanorods generate strong green PL bands located at about 510 and 521 nm and weak PL band located at about 654 nm, which are related to the defects in the molybdenum oxide nanorods. The outcomes can enrich our knowledge on the synthesis and optical properties of molybdenum oxide nanomaterials and contribute to the development of optoelectronic devices related to molybdenum oxide nanomaterials.