Fabrication of an acetone gas sensor based on Si doped WO3 nanorods prepared by reactive magnetron co-sputtering with OAD technique

Gas sensing technology is currently applied in a variety of applications. In medical applications, gas sensors can be used for the detection of the biomarker in various diseases, metabolic disorders, diabetes mellitus, asthma, renal, liver diseases, and lung cancer. In this study, we present acetone sensing characteristics of Si-doped WO3 nanorods prepared by a DC reactive magnetron co-sputtering with an oblique-angle deposition (OAD) technique. The composition of Si-doped in WO3 has been studied by varying the electrical input power applied to the Si sputtered target. The nanorods film was constructed at the glancing angle of 85°. After deposition, the films were annealed at 400 ◦C for 4 hrs in the air. The microstructures and phases of the materials were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FESEM). The results showed that 1.43 wt% Si-doped WO3 thin film exhibited the maximum response of 5.92 towards 100 ppm of acetone at performing temperature (350 °C), purifying dry air carrier. The process exposed in this work demonstrated the potential of high sensitivity acetone gas sensor at low concentration and may be used as an effective tool for diabetes non-invasive monitoring.

Nanostructuring at oblique incidence deposition of cobalt

Nanocolumnar Co thin films growth by oblique angle deposition on Si substrate is experimentally studied. Formation of regular arrays of tilted Co nanocolumns has been observed at incidence angles more than 70°. It was found that the optimal conditions for nanostructuring are realized at the inclination angle 85°. As obtained films have magnetic anisotropy axis inclined to the substrate surface and oriented along nanocolumns. Such films might be perspective material for applications as a magnetic recording media for next generations of hard disks.

Excitation of Surface Plasmon-Polariton Wave at Both Interfaces of a Silver Thin Film in Two-Layer Kretschmann geometry

In this work, a TiO2-Ag composite structure was fabricated by combination of physical vapor deposition and oblique angle deposition. The nanostructure of the TiO2 columnar thin film was analyzed using the field emission scanning electron microscopy. The excitation of the surface plasmon-polariton waves was studied using an optical setup that is called the two-layer Kretschman geometry. The results showed that two surface plasmon-polariton modes are propagated for TiO2 dielectric thin film at oblique deposition that they are related to metal-air and TiO2 - metal interfaces. The surface plasmon-polariton modes were more localized on interfaces at glancing angles of incident flux vapor. In normal incident of flux vapor only one surface plasmon-polariton mode can be excited at interface of metal-air. The results of this research may be applied in simultaneous sensing of the different molecules, chemical species and nanoparticles with different sizes.

Broadband Anti-Reflection Coatings Fabricated by Precise Time-Controlled and Oblique-Angle Deposition Methods

Broadband anti-reflection (AR) coatings are essential elements for improving the photocurrent generation of photovoltaic modules and enhancing visibility in optical devices. In this paper, we report a hybrid-structured, anti-reflection coating that combines multi-layer thin films with a single top-oblique deposited layer. By simply introducing this low-refractive index layer, the broadband anti-reflection properties of optical thin films can be improved while simplifying the preparation. Precise time-controlled and oblique-angle deposition (OAD) methods were used to fabricate the broadband AR coating. By accurately measuring and adjusting the design errors for the thin and thick film layers, 22-layer and 36-layer AR coatings on a sapphire substrate with a 400–2000 nm wideband were obtained. This bottom-up preparation process and AR coating design have the potential to significantly enhance the broadband antireflective properties for many optical systems and reduce the manufacturing cost of broadband AR coatings.