Active-electrode biosensor of SnO nanowire for cyclodextrin detection from microbial enzyme.

Cyclodextrin (CD) is a conical compound used in food and pharmaceutical industry to complexation of hydrophobic substances. It is a product of microbial enzymes which converts starch into CD during their activity. We aim to detect CD using active-electrode biosensor of SnO.

Computational Chemistry Meets Experiments for Explaining the Geometry, Electronic Structure, and Optical Properties of CaVO.

In this paper, we present a combined experimental and theoretical study to disclose, for the first time, the structural, electronic, and optical properties of CaVO crystals. The microwave-assisted hydrothermal (MAH) method has been employed to synthesize these crystals with different morphologies, within a short reaction time at 120 °C. First-principle quantum mechanical calculations have been performed at the density functional theory level to obtain the geometry and electronic properties of CaVO crystal in the fundamental and excited electronic states (singlet and triplet).

Understanding the fundamental electrical and photoelectrochemical behavior of a hematite photoanode.

Hematite is considered to be the most promising material used as a photoanode for water splitting and here we utilized a sintered hematite photoanode to address the fundamental electrical, electrochemical and photoelectrochemical behavior of this semiconductor oxide. The results presented here allowed us to conclude that the addition of Sn(4+) decreases the grain boundary resistance of the hematite polycrystalline electrode. Heat treatment in a nitrogen (N2) atmosphere also contributes to a decrease of the grain boundary resistance, supporting the evidence that the presence of oxygen is fundamental for the formation of a voltage barrier at the hematite grain boundary.

Grazing angle photoluminescence of porous alumina as an analytical transducer for gaseous ethanol detection.

Porous alumina was used to build an optical sensor for gaseous ethanol detection. The photoluminescence collected in a grazing angle was used as a transducer signal. The photoluminescence detected with this optical setup shows well resolved Fabry-Pérot type interference fringes at room temperature, whose position and shape are strongly dependent on the ethanol fraction adsorbed on the porous alumina surface.

Back-to-back Schottky diodes: the generalization of the diode theory in analysis and extraction of electrical parameters of nanodevices.

We report on the analysis of nonlinear current-voltage characteristics exhibited by a set of blocking metal/SnO(2)/metal. Schottky barrier heights in both interfaces were independently extracted and their dependence on the metal work function was analyzed. The disorder-induced interface states effectively pinned the Fermi level at the SnO(2) surface, leading to the observed Schottky barriers.

Measuring the mobility of single crystalline wires and its dependence on temperature and carrier density.

Kinetic transport parameters are fundamental for the development of electronic nanodevices. We present new results for the temperature dependence of mobility and carrier density in single crystalline In(2)O(3) samples and the method of extraction of these parameters which can be extended to similar systems. The data were obtained using a conventional Hall geometry and were quantitatively described by the semiconductor transport theory characterizing the electron transport as being controlled by the variable range hopping mechanism.

Magnetoresistance in Sn-Doped In2O3Nanowires.

In this work, we present transport measurements of individual Sn-doped In2O3nanowires as a function of temperature and magnetic field. The results showed a localized character of the resistivity at low temperatures as evidenced by the presence of a negative temperature coefficient resistance in temperatures lower than 77 K. The weak localization was pointed as the mechanism responsible by the negative temperature coefficient of the resistance at low temperatures.

Electron dephasing and weak localization in Sn doped In(2)O(3) nanowires.

We report on (magneto-) transport measurements of individual In2O3 nanowires. We observed that the presence of a weak disorder arising from doping and electron-boundary collisions leads to weak localization of electrons as revealed by the positive magnetoconductivity in a large range of temperatures ( approximately 77 K). From temperature-dependent resistance and magnetoconductivity data, the electron-electron interaction was pointed out as the mechanism responsible for the increase of resistance in the low temperature range and the dominant source of the dephasing at low temperatures.

Deposition of controlled thickness ultrathin SnO2:Sb films by spin-coating.

The technological interest in transparent conductive oxide films (TCOs) has motivated several works in processing techniques, in order to obtain adequate routes to application. In this way, this work describes a new route to obtain antimony-doped tin oxide (ATO) films, based in colloidal dispersions of oxide nanocrystals. The nanoparticles were obtained by a hydrolisis method, using SnCl2 and SbCl3 in ethanolic solutions.