We report on a novel lithography technique for patterning of hydrogen-passivated amorphous silicon surfaces. A reflection mode scanning near-field optical microscope with uncoated fiber probes has been used to locally oxidize a thin amorphous silicon layer. Lines of 110 nm in width, induced by the optical near field, were observed after etching in potassium hydroxide. The uncoated fibers can also induce oxidation without light exposure, in a manner similar to an atomic force microscope, and linewidths of 50 nm have been achieved this way.
Abstract-We present microfabrication and characterization of truly three-dimensional (3-D) diffuser/nozzle structures in silicon. Chemical vapor deposition (CVD), reactive ion etching (RIE), and laser-assisted etching are used to etch flow chambers and diffuser/nozzle elements. The flow behavior of the fabricated elements and the dependence of diffuser/nozzle efficiency on structure geometry has been investigated. The large freedom of 3-D micromachining combined with rapid prototyping allows to characterize and optimize diffuser/nozzle structures. [199]
A laser direct-write process has been applied to structure silicon on a nanometer scale. In this process, a silicon substrate, placed in a chlorine ambience, is locally heated above its melting point by a continuous-wave laser and translated by high-resolution direct-current motor stages. Only the molten silicon reacts spontaneously with the molecular chlorine, resulting in trenches with the width of the laser-generated melt. Trenches have been etched with a width of less than 70 nm. To explain the functional dependence of the melt size on absorbed power, the calculations based on a two-phase steady state heat model are presented, taking the temperature-dependent thermal conductivities and optical parameters into account.
Background Hypoglycaemia is the most frequent complication of treatment with insulin or insulin secretagogues in people with diabetes. Severe hypoglycaemia, i.e. an event requiring external help because of cognitive dysfunction, is associated with a higher risk of adverse cardiovascular outcomes and all-cause mortality, but underlying mechanism(s) are poorly understood. There is also a gap in the understanding of the clinical, psychological and health economic impact of 'non-severe' hypoglycaemia and the glucose level below which hypoglycaemia causes harm.Aim To increase understanding of hypoglycaemia by addressing the above issues over a 4-year period.Methods Hypo-RESOLVE is structured across eight work packages, each with a distinct focus. We will construct a large, sustainable database including hypoglycaemia data from >100 clinical trials to examine predictors of hypoglycaemia and establish glucose threshold(s) below which hypoglycaemia constitutes a risk for adverse biomedical and psychological outcomes, and increases healthcare costs. We will also investigate the mechanism(s) underlying the antecedents and consequences of hypoglycaemia, the significance of glucose sensor-detected hypoglycaemia, the impact of hypoglycaemia in families, and the costs of hypoglycaemia for healthcare systems.
Deep-level defects in as-grown, ingot-annealed, and wafer-annealed samples of semi-insulating gallium arsenide have been investigated by spatially resolved measurements of room-temperature photoluminescence, infrared absorption, free-carrier lifetime, and resistivity. High-temperature ingot annealing mainly causes a homogenization of the EL2 distribution. Rapid cooling from a wafer annealing process at T>900 °C suppresses the formation of the previously lifetime-limiting recombination center. After wafer annealing the EL2 defect may be the dominant recombination center, while in as-grown and ingot-annealed material lifetime is limited by a different trap. There is experimental evidence that this trap is related to the 0.8-eV luminescence band and that its density is spatially anticorrelated to the EL2 distribution. Based on lifetime measurements and a correlation of EL2 and photoluminescence topographs, we developed a recombination model, which explains the relationship between defect densities, and photoluminescence. The effect of surface recombination is described by a numerical calculation.
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