| As important semiconductor material, Vanadium oxide （VOx） has a greatpotential value due to its good optical, electrical properties. It can be applied in thetemperature sensor, photoelectric regulator, rechargeable lithium-ion batteries, smartwindows, uncooled infrared detectors, gas sensors, mask, fast photoelectric switchesand optical memory. Over the past few year, Vanadium oxide bulk materials havebeen studied in depth. Vanadium oxide nanomaterials have gradually become a hottopic of current research.In this paper, new approaches were developed in the preparation of VOx-based,one-dimensional and two-dimensional materials. Detailed analysis and theoreticalinterpretation were then proposed. A few sample of nanosensors were made by theirown characteristics.Ultralong single crystalline vanadium pentoxide （V2O5） nanobelts weresynthesized on silicon substrates using the modified chemical vapor deposition（MCVD）,which have width in20-500nm, length in centimeter magnitude, and theaspect ratio in more than five orders of magnitude. The growth conditions,morphology, crystallization and growth mechanism were studied. Vanadiumpentoxide nanobelts have optimal growth direction in [010] crystallization.A photoelectric switch with ultrafast response to visible light （<100μs）, suitablephotosensitivity and excellent repeatability is proposed based on the ultralong singlecrystalline V2O5nanobelt. Its photoconductive mechanism can well be explained bysmall polaron hopping theory. Moreover, a switching test circuit, including a LEDlight, displays the practicality of the switch.The possibility of usage in strain sensors and gas sensors were also discussed.V2O5nanobelt has obvious piezoresistive effect. Due to its sensitiveness to externalforces, good repeatability and good stability, V2O5nanobelt is very suitable formaking nanostrain sensors. Phase transition is not the mechanism of its piezoresistiveeffect.A single V2O5nanobelt has a low sensitivity to ammonia and nitrogen dioxide asgas sensor. Array integration and other gas test need to be done for further research.Vanadium film was deposited by Magnetron sputtering. After that, it wasoxidized by laser direct writing （LDW）. The oxidation threshold of the laser in the metal vanadium film is7mW cm-2. X-ray photoelectron spectroscopy （XPS） was usedto analyse the chemical composition of VOxthin films. The relationship between thelaser power density and the valence state of VOxthin films was established initially,where10mW cm-2and20mW cm-2power density correspond to main VO2and V2O5,respectively. In addition, the power density has relationship with the gray-scale andheight of VOxthin films. |
