Spire Corporation

United States of America As Represented by the Secretary of the Air Force

Fereydoon Namavar

Nader Montazemezam Kalkhoran

Richard A Soref

H Paul Maruska

The present invention provides orthopedic prosthesis having at least one metallic component that includes a metallic substrate on which an integrally formed nano-crystalline coating is formed. The coating and the substrate have at least one metallic constituent in common having an average atomic concentration in the coating that differs from an average atomic concentration in the substrate by less than about 10 percent. Further, the nano-crystalline coatings includes crystalline grains with an average size in a range of about 1 to 999 nanometers, and more preferably in a range of about 10 to 200 nanometers. A transition region that exhibits a graded reduction in average grain size separates the coating from the substrate. The coating advantageously exhibits an enhanced hardness, and a high degree of resistance to corrosion and wear. In one application, the nano-crystalline coatings of the invention are utilized to form articulating surfaces of various orthopedic devices.

Nano-crystalline, homo-metallic, protective coatings

A low-cost Si-based construction for optical and electronic bulk-heterostructure devices and multiple-quantum-well devices in which the active layers of the device are SiC or AlGaN or InGaN or InAlN. Material quality is high, and the MQW devices such as blue light lasers or LEDs have stable pseudomorphic layers with low defect densities. The low-cost large-area 3C SiC substrate is created by converting 100% of a 100-500 angstrom (.ANG.) layer of Si in a silicon-on-insulator wafer to 3C SiC with propane at 1300 degrees C. The SiO2 layer provides strain-free support for the 'perfect' 3C SiC crystal layer. Direct-gap wurtzite nitride heterostructures, bulk or pseudomorphic MQW, are grown upon an (0001) 6H SiC epilayer on the (111) 3C SIC substrate, or directly upon the (111) 3C SiC substrate. For zincblende heterostructures, a (100) 3C SiC substrate is used.

SiC/111-V-nitride heterostructures on SiC/SiO.sub.2 /Si for

A wavelength selective photodetector including: a substrate having a buried insulator layer for electrically isolating a lower section of the substrate located below the insulator layer from an upper section of the substrate located above the insulator layer; and a photon detector formed on the upper section of the substrate for detecting photons in a selected wavelength range, wherein the upper section has a selected thickness and the thickness determines at least in part the selected wavelength range of the detected photons.

Wavelength selective photodetector

A multi-band spectroscopic photodetector array including a substrate having a buried insulator layer in the substrate for electrically isolating a lower section of the substrate located below the insulator layer form an upper section of the substrate located above the insulator layer; and a plurality of photodetection elements each formed on a different portion of the upper layer and each including elements for detecting photons in a selected wavelength range; wherein each of the different portions of the upper section has a different thickness and wherein the thickness at least in part determines the selected wavelength of the photons detected by each of the detection elements.

Multi-band spectroscopic photodetector array

High performance GaAs and AlGaAs-based devices and a process enabling the manufacture of new III-V compound technologies are disclosed. The GaAs devices are particularly useful as VLSICs by possessing a high degree of electrical insulation, both vertical and lateral, between closely packed active devices. Essentially, the GaAs devices include a substrate on which is formed, preferably by epitaxial growth or by ion implantation, an active GaAs, or AlGaAs region incorporating, by appropriate doping, the simultaneously therein formed active segments. The active segments are electrically shielded by providing insulating stratums in the active GaAs, AlGaAs region surrounding the active segments. Preferably, the insulating stratums are formed therein by implanting arsenic ions therein so as to form arsenic precipitates. Preferably, a passivated surface layer also is formed in part of the surface of the GaAs, AlGaAs active layer, also preferably by implanting arsenic ions therein. Following implantation, the GaAs, AlGaAs devices are annealed in a reactor preferably at a temperature of about 600.degree. C. in an arsine ambient gas for a period of about 10 minutes.

High performance gaas devices and method

A solid state optoelectronic switching and display device and a method for its manufacture are disclosed. The device, formed in silicon, essentially is a surface-emitting visible light-emitting diode that allows rapid and efficient switching and information transfer, via optical means, between IC's, PC boards and displays in a computer. The method essentially includes electrochemically etching a silicon wafer to form a porous silicon region therein, depositing a transparent semiconductor layer on the porous silicon region, and forming a back contact on the wafer.

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Westford, MA, United States of America

Fereydoon Namavar