Modified Wurtzite Structure Oxide Compounds as Substrates for III-V Nitride Compound Semiconductor Epitaxial Growth

Semiconductor light emitting and sensing devices are comprised of a lattice matching wurtzite structure oxide substrate and a III-V nitride compound semiconductor single crystal film epitaxially grown on the substrate. Single crystals of these oxides are grown and the substrates are produced. The lattice matching substrates include Lithium Aluminum Oxide (LiAlO.sub.2), Lithium Gallium Oxide (LiGaO.sub.2), Lithium Silicon Oxide (Li.sub.2 SiO.sub.3), Lithium Germanium Oxide (Li.sub.2 GeO.sub.3), Sodium Aluminum Oxide (NaAlO.sub.2), Sodium Gallium Oxide (NaGaO.sub.2), Sodium Germanium Oxide (Na.sub.2 GeO.sub.3), Sodium Silicon Oxide (Na.sub.2 SiO.sub.3), Lithium Phosphor Oxide (Li.sub.3 PO.sub.4), Lithium Arsenic Oxide (Li.sub.3 AsO.sub.4), Lithium Vanadium Oxide (Li.sub.3 VO.sub.4), Lithium Magnesium Germanium Oxide (Li.sub.2 MgGeO.sub.4), Lithium Zinc Germanium Oxide (Li.sub.2 ZnGeO.sub.4), Lithium Cadmium Germanium Oxide (Li.sub.2 CdGeO.sub.4), Lithium Magnesium Silicon Oxide (Li.sub.

Lutetium Yttrium Orthosilicate Single Crystal Scintillator Detector

A single crystal having the general composition, Ce.sub.2x (Lu.sub.1-y Y.sub.y).sub.2(1-x) SiO.sub.5 where x=approximately 0.00001 to approximately 0.05 and y=approximately 0.0001 to approximately 0.9999; preferably where x ranges from approximately 0.0001 to approximately 0.001 and y ranges from approximately 0.3 to approximately 0.8. The crystal is useful as a scintillation detector responsive to gamma ray or similar high energy radiation. The crystal as scintillation detector has wide application for the use in the fields of physics, chemistry, medicine, geology and cosmology because of its enhanced scintillation response to gamma rays, x-rays, cosmic rays and similar high energy particle radiation

Lutetium Yttrium Orthosilicate Single Crystal Scintillator Detector

A single crystal having the general composition, Ce.sub.2x (Lu.sub.1-y Y.sub.y).sub.2(1-x) SiO.sub.5 where x=approximately 0.00001 to approximately 0.05 and y=approximately 0.0001 to approximately 0.9999; preferably where x ranges from approximately 0.0001 to approximately 0.001 and y ranges from approximately 0.3 to approximately 0.8. The crystal is useful as a scintillation detector responsive to gamma ray or similar high energy radiation. The crystal as scintillation detector has wide application for the use in the fields of physics, chemistry, medicine, geology and cosmology because of its enhanced scintillation response to gamma rays, x-rays, cosmic rays and similar high energy particle radiation

Method and apparatus for producing group-III nitrides

The subject invention pertains to a method and device for producing large area single crystalline III-V nitride compound semiconductor substrates with a composition AlxInyGal-x-y N (where O?x?1, 0?y?1, and 0?x+y?1). In a specific embodiment, GaN substrates, with low dislocation densities (˜107 cm2) can be produced. These crystalline III-V substrates can be used to fabricate lasers and transistors. Large area free standing single crystals of III-V compounds, for example GaN, can be produced in accordance with the subject invention. By utilizing the rapid growth rates afforded by hydride vapor phase epitaxy (HVPE) and growing on lattice matching orthorhombic structure oxide substrates, good quality III-V crystals can be grown. Examples of oxide substrates include LiGaO2, LiAlO2, MgAlScO4, Al2MgO4, and LiNdO2. The subject invention relates to a method and apparatus, for the deposition of III-V compounds, which can alternate between MOVPE and HVPE, combining the advantages of both. In particular, the subject hybrid reactor can go back and forth between MOVPE and HVPE in situ so that the substrate does not have to be transported between reactor apparatus and, therefore, cooled between the performance of different growth techniques

Flashlamp Pumped Cr-Lisralf6 Laser

Tunable, flashlamp-pumped laser properties are described for the crystal Cr:LiSrAlF6 (Cr:LiSAF) in both long pulse and Q-switched modes of operation. Slope efficiencies of 5%, overall efficiency of 3%, and a tuning range from 780 to 1010 nm are reported

1.3um Lasers Using Nd3+ Doped Apatite Crystals

Laser pumping and flashlamp pumping of apatite crystals such as trivalent neodymium-doped strontium fluorapatite (Sr.sub.5 (PO.sub.4).sub.3 F) emits efficient lasing at both 1.059 and 1.328 .mu.m. The pump sources for the SFAP material doped with Nd.sup.3+ includes pulsed Cr:LiSrAlF.sub.6 tuned to approximately 805.4 nm. Alternatively, similar results occurred using a continuous wave laser source of Ti:sapphire tuned to approximately 805.4 nm. A preferred embodiment includes a resonant cavity with a high reflectivity mirror having a reflectivity of 100% and an output coupler mirror with a reflectivity of less than 100%. An optional tuning component such as a Pockels Cell-Polarizer combination can also be included. The SFAP material doped with Nd.sup.3+ exhibits a large absorption cross section, high emission cross section, and long radiative lifetime

Yb-Doped: YCOB Laser (DIV)

A tunable, solid state laser device with both visible and infrared laser emission is developed with a trivalent ytterbium-doped yttrium calcium oxyborate crystal as the host crystal. The Yb:YCOB crystal generates an infrared fundamental light over a wide bandwidth, from approximately 980 nanometers (nm) to approximately 1100 nm. The bandwidth generated by the Yb:YCOB crystal is approximately 100 nm wide and supports the generation of pulsed infrared light or when self-frequency doubled provides a compact, efficient, source of tunable, visible, blue or green laser light in wavelengths of approximately 490 nm to approximately 550 nm

Self Frequency-doubled Nd-doped YCOB Laser

Neodymium-doped yttrium calcium oxyborate (Nd:YCOB) is the single active gain element for a solid-state laser device capable of achieving both lasing and self-frequency doubling optical effects. A pumping source for optically pumping Nd:YCOB can generate a laser light output of approximately 400 mW at approximately 1060 nm wavelength and a self-frequency doubled output of approximately 60 mW at approximately 530 nm wavelength. Thus, a laser device can be designed that is compact, less expensive and a high-powered source of visible, green laser light

Understanding the Roles of the Kynurenine Pathway in Multiple Sclerosis Progression

The kynurenine pathway (KP) is a major degradative pathway of tryptophan ultimately leading to the production of nicotinamide adenine dinucleotide (NAD+) and is also one of the major regulatory mechanisms of the immune response. The KP is known to be involved in several neuroinflammatory disorders including Alzheimer’s disease, amyotrophic lateral sclerosis, AIDS dementia complex, Parkinson’s disease, schizophrenia, Huntington’s disease and brain tumours. However, the KP remains a relatively new topic for the field of multiple sclerosis (MS). Over the last 2–3 years, some evidence has progressively emerged suggesting that the KP is likely to be involved in the pathogenesis of autoimmune diseases especially MS. Some KP modulators are already in clinical trials for other inflammatory diseases and would potentially provide a new and important therapeutic strategy for MS patients. This review summarizes the known relationships between the KP and MS

Neodymium-Doped Sr-5(Po4)(3)F And Sr-5(Vo4)(3)F

Neodymium-doped Sr-5(PO4)(3)F [neodymium strontium fluoride phosphate, (Nd,Sr)(5)(PO4)(3)F] and neodymium-doped Sr-5(VO4)(3)F [neodymium strontium fluoride vanadate, (Nd,Sr)(5)(VO4)(3)F] crystallize in space group P6(3)/m and are isostructural with calcium fluorophosphate, Ca-5(PO4)(3)F. There are two different Sr sites in Sr-5(XO(4))(3)F, denoted Sr(1) and Sr(2). Using single-crystal X-ray diffraction the two structures were refined to R factors of 2.3 and 2.2%, respectively, showing that Nd is present at both Sr sites in (Sr,Nd)(5)(VO4)(3)F but only at the Sr(2) site in (Sr,Nd)(5)(PO4)(3)F