Tin Oxide Nanorod Array-Based Electrochemical Hydrogen Peroxide Biosensor

SnO2 nanorod array grown directly on alloy substrate has been employed as the working electrode of H2O2 biosensor. Single-crystalline SnO2 nanorods provide not only low isoelectric point and enough void spaces for facile horseradish peroxidase (HRP) immobilization but also numerous conductive channels for electron transport to and from current collector; thus, leading to direct electrochemistry of HRP. The nanorod array-based biosensor demonstrates high H2O2 sensing performance in terms of excellent sensitivity (379 μA mM−1 cm−2), low detection limit (0.2 μM) and high selectivity with the apparent Michaelis–Menten constant estimated to be as small as 33.9 μM. Our work further demonstrates the advantages of ordered array architecture in electrochemical device application and sheds light on the construction of other high-performance enzymatic biosensors

Zirconium tin titanate thin films via aqueous polymeric precursor route

Zirconium titanate-based thin films are considered as a promising dielectric material for the next generation of integrated microwave devices. The zirconium tin titanate (ZTS) precursor was prepared via a polymeric precursor process in aqueous phase. based on the citrate route. The presented chemical procedure is original for this kind of materials. C-13 nuclear magnetic resonance (NMR) spectra showed that stable mixed-metal chelate complex has been formed. The viscous resin was multiple spin-coated with intermediate firings at 300 degreesC onto platinized Si substrates and fired in air at 700 degreesC. Thin films 200-nm thick were obtained. Atomic force microscope (AFM) analysis showed that the coverage is homogeneous, the surface texture consisting of elongated grains of average size 20 X 36 nm. Grazing incidence X-ray diffraction analysis (GIXRD) indicated that only the zirconium tin titanate phase is present within the examined range of penetration depth. (C) 2001 Elsevier Science BN. AA rights reserved

Characterization of Ga2O3 based MRISiC hydrogen gas sensors

This paper presents the results of our investigations on the hydrogen gas response of Pt/Ga2O3/SiC devices operated as Schottky diodes highlighting the importance of gallium oxide as a layer within the device. The Ga2O3 thin films were prepared using the sol¿gel technique. The investigation reported in this paper also includes the compositional characterization of the Ga2O3 films using X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS). Results show the films consisted of stoichiometric Ga2O3, with a thickness of less than 100 nm. RBS analysis indicated that the films are stoichiometric and reproducible. For gas sensing experiments, the diodes were biased at a constant current varying between 1 and 2 mA and their responses to H2 in different ambient was measured. The sensors were extremely stable, varying from its mean baseline value by only 0.014%. When operated in oxygen rich ambient the magnitude of the responses was larger. The response and recovery times also appear to be large, owing to nearly total interaction or combustion of the dissociated hydrogen molecules on the surface of the device

Photoelectrical Properties of 1.3μm Emitting InAs Quantum Dots in InGaAs Matrix

We present a study of photoelectrical properties of the Stranski-Krastanow InAs quantum dots embedded in an InGaAs matrix with low In content, emitting at about 1.3μm. The ground-state electron-hole transition of the dots was investigated as a function of the temperature in presence of electric fields parallel and perpendicular to the plane of the dots by photocurrent spectroscopy. Microphotoluminescence measurements were also carried out, allowing us to evidence carrier capture from the GaAs matrix into the dots