Side-by-Side In(OH)3 and In2O3 Nanotubes: Synthesis and Optical Properties

A simple and mild wet-chemical approach was developed for the synthesis of one-dimensional (1D) In(OH)3 nanostructures. By calcining the 1D In(OH)3 nanocrystals in air at 250 °C, 1D In2O3 nanocrystals with the same morphology were obtained. TEM results show that both 1D In(OH)3 and 1D In2O3 are composed of uniform nanotube bundles. SAED and XRD patterns indicate that 1D In(OH)3 and 1D In2O3 nanostructures are single crystalline and possess the same bcc crystalline structure as the bulk In(OH)3 and In2O3, respectively. TGA/DTA analyses of the precursor In(OH)3 and the final product In2O3 confirm the existence of CTAB molecules, and its content is about 6%. The optical absorption band edge of 1D In2O3 exhibits an evident blueshift with respect to that of the commercial In2O3 powders, which is caused by the increasing energy gap resulted from decreasing the grain size. A relatively strong and broad purple-blue emission band centered at 440 nm was observed in the room temperature PL spectrum of 1D In2O3 nanotube bundles, which was mainly attributed to the existence of the oxygen vacancies

Broadband Coupling into a Single-Mode, Electroactive Integrated Optical Waveguide for Spectroelectrochemical Analysis of Surface-Confined Redox Couples

Pushing the sensitivity of spectroelectrochemical techniques to routinely monitor changes in spectral properties of thin molecular films (i.e., monolayer or submonolayer) adsorbed on an electrode surface has been a goal of many investigators since the earliest developments in this field. 1 It was initially recognized that exploiting the evanescent field generated by total internal reflection at the interface of an optically transparent electrode (such as a thin film of tin oxide or indium tin oxide (ITO) on glass or quartz) has the inherent advantage of selectively probing only the near-surface region, as opposed to bulk sampling with transmission based techniques. Furthermore, by utilizing the multiple reflections in an attenuated total reflectance (ATR) geometry, an enhancement in sensitivity can be realized, and as the thickness of the ATR element is decreased, the number of reflections increases, yielding a substantial sensitivity enhancement. [2][3][4][5][6] Itoh and Fujishima were the first to show the advantages of reducing the thickness of an ATR element overcoated with a transparent conductive oxide to the integrated optical waveguide (IOW) regime. Using a four-mode, gradient index waveguide coated with a transparent, conductive tin oxide layer, they demonstrated large sensitivity enhancements, relative to a single pass transmission experiment, for spectroelectrochemical measurements of methylene blue. 7,8 Other research groups subsequently described similar gradient index, multilayer, electroactive waveguide structures, but they did not make use of the technology to explore the spectroelectrochemistry of (sub)monolayer coverage films. [9][10][11][12][13] We recently described a single-mode, electroactive planar IOW (the EA-IOW) having a step refractive index profile. It was fabricated by sputtering a Corning 7059 glass layer (400 nm) over soda lime glass or quartz, followed by a 200-nm layer of SiO 2

Deposition of hetero-epitaxial In{sub 2}O{sub 3} thin films by molecular beam epitaxy

Highly oriented thin film In{sub 2}O{sub 3} was heteroepitaxially grown on optically polished (100) plane of single crystalline yttria stabilized zirconia (YSZ) substrate using Molecular Beam Epitaxy (MBE). Full-width at half-maximum (FWHM) of X-ray rocking-curve showed 0.08{degree} for In{sub 2}O{sub 3} 200 nm thick layers indicating that excellent uniformity orientation compared with the heteroepitaxially-grown In{sub 2}O{sub 3} epitaxially deposited by the conventional methods such as electron-beam (e-beam) evaporation or sputtering method. The minimum yield ({chi}{sub min}) of the MBE grown in In{sub 2}O{sub 3} film of Rutherford Backscattering Spectrometry (RBS) was also extremely small value 3.1%, implying the very high crystallinity

High rate deposition of tin-doped indium oxide films by reactive magnetron sputtering with unipolar pulsing and plasma emission feedback systems

Tin-doped indium oxide (ITO) films were deposited on the unheated alkali-free glass substrates (AN100) by reactive magnetron sputtering using an indium-tin alloy target with an unipolar pulsed power source feeding 50 kHz pulses and a plasma control unit (PCU) with a feed back system of oxygen plasma emission intensity at 777 nm. In order to achieve very high deposition rates, depositions were carried out in the 'transition region' between the metallic and the reactive (oxide) sputter modes where the target surface was metallic and oxidized, respectively. Stable depositions were successfully carried out in the whole 'transition region' with an aid of PCU. The lowest resistivity as the transparent ITO films deposited on unheated alkali-free glass was 7.5×10?4 ?cm with the deposition rate of 650 nm/min. The electrical and optical properties of the films could be controlled systematically in the very wide range