Rapid Synthesis And Characterization Of Micro And Nanostructures Of Molybdenum Trioxide

Micro - and nanostructures of molybdenum trioxide (MoO3) have been investigated intensively for sensorial and electrochromic systems. MoO 3 nanostructures were grown by a rapid thermal oxidation of molybdenum at 1000°C in oxygen environment. Its structural, morphological and optical properties were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-Raman and optical transmission techniques. This work presents a new technique for facile synthesis of MoO3 nanostructures via thermal oxidation, and the results of exploration of their properties. MoO3 is found to consist of stratified long micro/nano-ribbons and nanowires promising for applications in sensor and other device structures. © 2013 IEEE

Copper Doped Zinc Oxide Micro- And Nanostructures For Room-Temperature Sensorial Applications

Detection of hydrogen gas is important for safety reasons. To obtain improved hydrogen sensing performances for miniaturized sensors, copper doping in zinc oxide micro- and nanostructures were investigated. Samples were grown by hydrothermal technique at relatively low temperature and studied by X-ray diffraction, micro-Raman, SEM and sensorial techniques. It is found evidence on the improvement of the sensorial properties due to copper-doping in zinc oxide rods-like structures. © 2013 IEEE

Silver-Doped Zinc Oxide Single Nanowire Multifunctional Nanosensor With A Significant Enhancement In Response

Enhanced performances were obtained for nanosensors based on a single nanowire of silver-doped zinc oxide (ZnO:Ag). Arrays of crystalline ZnO:Ag nanowires were synthesized by electrodeposition on F-doped tin oxide coated substrates and studied by SEM, EDX, TEM, HRTEM, SIMS, XPS, PL and micro-Raman spectroscopy. Integration of a single nanowire or a single microwire on the chip was performed by employing metal maskless nanodeposition in the dual beam focused electron/ion beam instrument. The ultraviolet (UV) response and hydrogen (H2) gas response were studied for nanodevices and microdevices based on a single ZnO:Ag nanowire. We found that ZnO:Ag nanowire based nanosensor possesses a much faster response/recovery time and a higher response to UV radiation and hydrogen gas (∼50%) than those reported in literature. An increase in current value of about two orders in magnitude IUVON/IUVOFF was observed under exposure to UV light. Faster response/recovery times of about 0.98 s/0.87 s were observed. The ZnO:Ag nanowires and microwires can serve as nano-building materials for ultrasensitive and ultra-fast sensors with reduced power consumption. The mechanisms for such improved responses to UV and H2 were discussed. The developed nanomaterial is of great scientific interest for further studies as promising candidates for fabricating multifunctional nano-sensors, LEDs and photodetectors by bottom-up and hybrid nanotechnologies

Effect of noble metal functionalization and film thickness on sensing properties of sprayed TiO2 ultra-thin films

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Versatile Growth of Freestanding Orthorhombic α‑Molybdenum Trioxide Nano- and Microstructures by Rapid Thermal Processing for Gas Nanosensors

We demonstrate a new technique that requires a relatively low temperature of 670–800 °C to synthesize in 10–20 min high crystalline quality MoO₃ nano- and microbelts and ribbons. The developed technological process allows rapid synthesis of large amounts of MoO₃ nano- and microsheets, belts, and ribbons, and it can be easily scaled up for various applications. Scanning electron microscopy (SEM) studies revealed that the MoO₃ nano- and microbelts and ribbons are synthesized uniformly, and the thickness is observed to vary from 20 to 1000 nm. The detailed structural and vibrational studies on grown structures confirmed an excellent agreement with the standard data for orthorhombic α-MoO₃. Also, such freestanding nano- and microstructures can be transferred to different substrates and dispersed individually. Using focused ion beam SEM, MoO₃-based 2D nano- and microsensors have been integrated on a chip and investigated in detail. The nanosensor structures based on MoO₃ nano- and microribbons are quite stable and moderately reversible with respect to rises and drops in ethanol vapors. It was found that MoO₃ nano- and microribbons of various sizes exhibit different sensitivity and selectivity with respect to ethanol, methanol, and hydrogen gases. The developed technique has great potential for further studies of different metal oxides, nano- and microsensor fabrication, and especially for multifunctional applications