RESUMO
Silicon microstructures only a few hundred atoms wide can be fabricated and used to study electron transport in narrow channels. Spatially localized voltage probes as close together as 0.1 micrometer can be used to investigate a variety of physical phenomena, including velocity saturation due to phonon emission, the local potentials caused by scattering from a single trapped electron, and quantum tunneling or hopping among very few electron states.
RESUMO
Research in microfabrication not only serves the microelectronics industry but also can provide research tools for studying the behavior of matter at submicrometer dimensions. A variety of techniques including optical, x-ray, and electron beam lithography and reactive ion etching can be used to make structures, devices, and arrays only hundreds of atoms across. Microfabrication techniques have been applied to experiments on surface-enhanced Raman scattering, transport in one-dimensional conductors, and macroscopic quantum tunneling. Recent progress is extending these techniques to scales of less than 100 angstroms.
RESUMO
The use of capacitive-mesh output couplers for optically pumped far-infrared molecular lasers has been extended throughout the far-infrared spectrum, between 42 microm and 1.2 mm, and the optimum grid constants have been found for several lines. At shorter wavelengths, performance has been improved by the use of a novel hybrid capacitive-mesh hole output coupler.
