Abstract:
A nanostructured composite material comprising semiconductor nanocrystals in a crystalline semiconductor matrix. Suitable nanocrystals include silicon, germanium, and silicon-germanium alloys, and lead salts such as PbS, PbSe, and PbTe. Suitable crystalline semiconductor matrix materials include Si and silicon-germanium alloys. A process for making the nanostructured composite materials. Devices comprising nanostructured composite materials.
Abstract:
Parallel flow chemical processing systems, such as parallel flow chemical reaction systems are disclosed. These systems are adapted to simultaneously and independently vary temperature between separate flow channels, preferably by employing separate, individual heating elements in thermal communication with each of four or more parallel flow reactors. The flow reactors are preferably isolated from each other using a thermal isolation system comprising fluid-based heat exchange. In preferred embodiments, the axial heat flux can be fixedly or controllably varied.
Abstract:
A process for synthesizing wide band gap materials, specifically, GaN, employs plasma-assisted and thermal nitridation with NH.sub.3 to convert GaAs to GaN. Thermal assisted nitridation with NH.sub.3 can be employed for forming layers of substantial thickness (on the order of 1 micron) of cubic and hexagonal GaN on a GaAs substrate. Plasma-assisted nitridation of NH.sub.3 results in formation of predominantly cubic GaN, a form particularly useful in optoelectronic devices. Preferably, very thin GaAs membranes are employed to permit formation thereon of GaN layers of any desired thickness without concern for critical thickness constraints. The thin membranes are preferably formed either with an epitaxial bonding technique, or by undercut etching.
Abstract:
Parallel flow reaction systems comprising four or more reaction channels are disclosed. Distribution systems, and parallel flow reaction systems comprising such distribution systems are also disclosed. Specifically, the distribution systems comprise a feed-composition subsystem for providing a different feed composition to each of the four or more reactors. In preferred embodiments, the feed composition subsystem comprises at least one set of four or more feed-component flow restrictors, each of the four or more feed-component flow restrictors having a flow resistance that varies relative to other flow restrictors in the set.
Abstract:
An apparatus and method for screening combinatorial libraries of materials by measuring the response of individual library members to mechanical perturbations is described. The apparatus generally includes a sample holder for containing the library members, an array of probes for mechanically perturbing individual library members, and an array of sensors for measuring the response of each of the library members to the mechanical perturbations. Library members undergoing screening make up a sample array, and individual library members constitute elements of the sample array that are confined to specific locations on the sample holder. During screening, the apparatus mechanically perturbs individual library members by displacing the sample array (sample holder) and the array of probes. Typically, all of the elements of the sample array are perturbed simultaneously, but the apparatus also can also perturb individual or groups of sample array elements sequentially. The flexible apparatus and method can screen libraries of materials based on many different bulk physical properties, including Young's modulus (flexure, uniaxial extension, biaxial compression, and shear); hardness (indentation), failure (stress and strain at failure, toughness), adhesion (tack, loop tack), and flow (viscosity, melt flow indexing, and rheology), among others.
Abstract:
Systems and methods for preparing inorganic-organic interfaces using organo-transition metal complexes and self-assembled monolayers as organic surfaces. In one embodiment, a silicon wafer is cleaned and reacted with stabilized pirhana etch to provide an oxide surface. The surface is reacted with the trichlorosilyl end of alkyltrichlorosilanes to prepare self assembling monomers (SAMs). The alkyltrichlorosilanes have the general formula R1-R—SiCl3, where R1 is —OH, —NH2, —COOH, —SH, COOCH3, —CN, and R is a conjugated hydrocarbon, such as (CH2)n where n is in the range of 3 to 18. The functionalized end of the SAM can optionally modified chemically as appropriate, and is then reacted with metal-bearing species such as tetrakis(dimethylamido)titanium, Ti[N(CH3)2]4, (TDMAT) to provide a titanium nitride layer.
Abstract:
Gas chromatographs of the invention generally comprise four or more analysis channels. Specifically, four or more gas chromatography columns are configured for parallel analysis of four or more gaseous samples with detection being effected using a microdetector array comprising four or more microdetectors. In one embodiment, the four or more microdetectors 510 are microfabricated detectors, and are integrally formed with a substrate or with one or more microchip bodies mounted on a substrate. In a preferred embodiment, a microdetector array comprises four or more thermal conductivity detectors having one or more thin-film detection filaments. A preferred heated environment for highly parallel gas chromatographs is also disclosed.
Abstract:
The present invention provides instruments and methods for screening combinatorial libraries that addresses many of the problems encountered when using conventional instruments. For example, the disclosed instruments can measure mechanical properties of library members in rapid serial or parallel test format, and can perform tests on small amounts of material, which are easily prepared or dispensed using art-disclosed liquid or solid handling techniques. Compared to conventional instruments, the disclosed instruments afford faster sample loading and unloading, for example, through the use of disposable libraries of material samples.
Abstract:
Parallel flow reaction systems comprising four or more reaction channels are disclosed. Distribution systems, and parallel flow reaction systems comprising such distribution systems are also disclosed. Specifically, the distribution systems comprise one or more subsystems, including for example, a flow-partitioning subsystem for providing a different flow rate to each of the four or more reactors, a pressure-partitioning subsystem for providing a different reaction pressure in the reaction cavity of each of the four or more reactors, and a feed-composition subsystem for providing a different feed composition to each of the four or more reactors. In preferred embodiments, the one or more subsystems can comprise at least one set of four or more flow restrictors, each of the four or more flow restrictors having a flow resistance that varies relative to other flow restrictors in the set.
Abstract:
A method for high throughput mechanical property and bulge testing of materials libraries. A plurality of samples on a substrate are monitored for their response to a force from a fluid.