Development of a Long-Wave Infrared Band-Edge (LWIR BE) thermometry instrument.

Accurate measurement of substrate temperature is one of the most critical process control parameters for molecular beam epitaxy (MBE) growth. Band-edge thermometry instruments have proven to be a valuable tool for process control during MBE growth of semiconductor films, providing as high as ±1 °C temperature resolution. The increasing use of InAs, GaSb, and AlSb iii-v materials necessitates a method for accurately measuring the temperature of their closely lattice-matched GaSb substrates.

Water cluster confinement and methane adsorption in the hydrophobic cavities of a fluorinated metal-organic framework.

Water cluster formation and methane adsorption within a hydrophobic porous metal organic framework is studied by in situ vibrational spectroscopy, adsorption isotherms, and first-principle DFT calculations (using vdW-DF). Specifically, the formation and stability of H2O clusters in the hydrophobic cavities of a fluorinated metal-organic framework (FMOF-1) is examined. Although the isotherms of water show no measurable uptake (see Yang et al.

Understanding the preferential adsorption of CO2 over N2 in a flexible metal-organic framework.

The unusual uptake behavior and preferential adsorption of CO(2) over N(2) are investigated in a flexible metal-organic framework system, Zn(2)(bdc)(2)(bpee), where bpdc = 4,4'-biphenyl dicarboxylate and bpee = 1,2-bis(4-pyridyl)ethylene, using Raman and IR spectroscopy. The results indicate that the interaction of CO(2) with the framework induces a twisting of one of its ligands, which is possible because of the type of connectivity of the carboxylate end group of the ligand to the metal center and the specific interaction of CO(2) with the framework. The flexibility of the bpee pillars allows the structure to respond to the twisting, fostering the adsorption of more CO(2).

Vibrational and electronic characterization of ethynyl derivatives grafted onto hydrogenated Si(111) surfaces.

Covalent grafting of ethynyl derivatives (-C triple bond C-H, -C triple bond C-CH3, -C triple bond C-aryl) onto H-terminated Si(111) surfaces was performed by a one-step anodic treatment in Grignard electrolytes. The electrochemical grafting of such ethynyl derivatives, which tends to form ultrathin polymeric layers, can be controlled by the current and charge flow passing through the Si electrode. The prepared ultrathin layers cover the Si surface and had a thickness up to 20 nm, as investigated by the scanning electron microscopy (SEM) technique.

Anisotropy in hydrogen-passivated and organically modified nanoporous silicon surfaces studied by polarization dependent IR spectroscopy.

Infrared spectroscopic ellipsometry (IRSE) was applied for characterization of porous silicon (PSi) electrochemically prepared in acidic fluoride solution. When no formation of SiO2 was involved in the preparation, an anisotropic distribution of PSi bonds with the terminating molecules was achieved. On the contrary, oxidation of PSi samples during the preparation led to an isotropic structure.