n/a

Different glasses based on the ZnO-B2O3-SiO2 system, with a ZnO content ≥ 60 mol% and a fixed SiO2 content (20 mol%), were synthesised using a melt-quenching method. Glass samples with zinc oxide concentrations as high as 65 mol% were prepared successfully without deteriorating the glass-forming ability. The glass samples were submitted to controlled heat-treatments, and the effect of the ZnO/B2O3 molar ratio on the formation of crystalline phases within the glass matrix was investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). DTA results indicated that the glass transition and the onset crystallization temperatures of the studied glasses tended to increase with the increment on the ZnO/B2O3 ratio. XRD data showed that the zinc binary crystalline phases, willemite (Zn2SiO4), a zinc orthosilicate, and zinc borate (Zn3B2O6) could be present in the crystallized glasses, depending on the heat-treatment conditions. The formation of willemite was promoted by an increasing ZnO/B2O3 ratio. Microstructural observations performed by SEM indicated that under controlled experimental parameters (glass composition, heat-treatment temperature and time) the precipitation of nanocrystals within the glass matrix can be achieved, resulting in transparent and translucent willemite glass-ceramics. © 2016 Elsevier B.V. All rights reserved.

High conductivity in the off-state and low field-effect mobility compared to bulk properties is widely observed in the p-type thin-film transistors of Cu2O, especially when processed at moderate temperature. This work presents results from in situ conductance measurements at thicknesses from sub-nm to around 250 nm with parallel X-ray photoelectron spectroscopy. An enhanced conductivity at low thickness is explained by the occurrence of Cu(II), which is segregated in the grain boundary and locally causes a conductivity similar to CuO, although the surface of the thick film has Cu2O stoichiometry. Since grains grow with an increasing film thickness, the effect of an apparent oxygen excess is most pronounced in vicinity to the substrate interface. Electrical properties of Cu2O grains are at least partially short-circuited by this effect. The study focuses on properties inherent to copper oxide, although interface effects cannot be ruled out. This non-destructive, bottom-up analysis reveals phenomena which are commonly not observable after device fabrication, but clearly dominate electrical properties of polycrystalline thin films. © 2016 Author(s).

Solution-processed p-type oxide semiconductors have recently attracted increasing interests for the applications in low-cost optoelectronic devices and low-power consumption complementary metal-oxide-semiconductor circuits. In this work, p-type nickel oxide (NiOx) thin films were prepared using low-temperature solution process and integrated as the channel layer in thin-film transistors (TFTs). The electrical properties of NiOx TFTs, together with the characteristics of NiOx thin films, were systematically investigated as a function of annealing temperature. By introducing aqueous high-k aluminum oxide (Al2O3) gate dielectric, the electrical performance of NiOx TFT was improved significantly compared with those based on SiO2 dielectric. Particularly, the hole mobility was found to be 60 times enhancement, quantitatively from 0.07 to 4.4 cm2/V s, which is mainly beneficial from the high areal capacitance of the Al2O3 dielectric and high-quality NiOx/Al2O3 interface. This simple solution-based method for producing p-type oxide TFTs is promising for next-generation oxide-based electronic applications. © 2016 Author(s).

This paper describes the development of a novel microfluidic platform for multifactorial analysis integrating four label-free detection methods: electrical impedance, refractometry, optical absorption and fluorescence. We present the rationale for the design and the details of the microfabrication of this multifactorial hybrid microfluidic chip. The structure of the platform consists of a three-dimensionally patterned polydimethylsiloxane top part attached to a bottom SU-8 epoxy-based negative photoresist part, where microelectrodes and optical fibers are incorporated to enable impedance and optical analysis. As a proof of concept, the chip functions have been tested and explored, enabling a diversity of applications: (i) impedance-based identification of the size of micro beads, as well as counting and distinguishing of erythrocytes by their volume or membrane properties; (ii) simultaneous determination of the refractive index and optical absorption properties of solutions; and (iii) fluorescence-based bead counting. © 2016 by the authors.