Silicon devices 492 INDEX

Properties of Porous Silicon, and Refractive Index of Porous Silicon ). Following the very first studies (Barla et al 1984 Drory et al. 1990), there have been continued but infrequent assessments (Da Fonesca et al 1995 Fang et al 2008 Rahmoun et al 2009 Aliev et al 2011 ). Nonetheless, there is a growing realization that robust porous silicon device and system performance will ultimately rely on achieving the appropriate mechanical properties, in conjunction with the novel functionality achieved through nanostructuring. 

The fiber optic refractive index sensor finds use in biomedical applications. It uses a silicon chip with optical waveguides forming ring resonators. When the laser wavelength is scanned, the resonators cause dips in the power transmitted through the device. The wavelength at which these dips occur is a measure of the refractive index of the substance in contact with the chip surface. 

Little change of viscosity makes silicone liquids indispensable damping devices and parts of various measuring devices. A drop of silicone liquid put on a pointer index in the cockpit prevents vibration and keeps the index at rest this kind of damping is more efficient than complicated mechanical devices. Silicone damping liquids are also used in speedometers, amperemeters, voltmeters and gasometers, in relays and breakers, in acoustic pickups. 

It may be helpful to express the change of viscosity of a silicone oil in a different manner. If we compare a typical silicone oil with a standard hydrocarbon oil of viscosity index 100, the two having the same viscosity at 100° F., we find that after cooling to —35° F. the silicone oil has seven times the viscosity it had, whereas the hydrocarbon oil has increased 1,800-fold in viscosity. This relative constancy of viscosity of the silicone oil makes it particularly suitable for use as a fluid in hydraulic systems for the transmission of power. Silicone oils do not react with the common metals of construction, and they are so inert that even at 300° F. they do not discolor r become acid or form sludge. They are satisfactory lubricants in hydraulic pumps and in any other device where conditions of hydrodynamic lubrication prevail. When used as lubricants, methyl silicone oils do not suffer loss of viscosity through shear breakdown under continuous load at high speed. 

The communications revolution also relies on a diverse set of CVD technologies. Some components are similar to those used in silicon microelectronics, but many are unique, involving complex epitaxial heterostructures of SiGe or compound semiconductor (e.g., AlGaAs) alloys that are required to yield high frequency (1-100 GHz) device operation. The communication revolution also relies on optoelectronic components, such as solid state diode lasers (another complex heterostructure device), and these devices are often grown by CVD. - Even the fiberoptic cables that transmit the optical component of the communications network are manufactured using a CVD technique to achieve the desired refractive index profile. ... 

The RM device consists of a high-index substrate ( 1 mm thick lead glass, = 1.72825), a thin low-index spacer (about 1000 nm of magnesium fluoride or silica) and a very thin monomode waveguiding layer (about 100 nm of titanium oxide, zirconium oxide, hafnium oxide or silicon nitride). It can be used to monitor re-... 

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