Abstract: An optical device includes a substrate having an electrooptical effect, and including an optical waveguide that guides light and a reflection groove having a bottom face that reflects light output from the optical waveguide; and a light-receiving element positioned above the reflection groove and fixed to the substrate. The light output from the optical waveguide into the reflection groove is reflected by the bottom face of the reflection groove while traveling through a space inside the reflection groove and is incident to the light-receiving element.

Abstract: Thin films of ferroelectric material with a high mole fraction of Pb(A2+1/3B5+2/3)O3 substantially in a perovskite phase, wherein A is zinc or a combination of zinc and magnesium, and B is a valence 5 element such as niobium or tantalum, have been prepared. Typically, the mole fraction of Pb(A2+1/3B5+2/3)O3 in the ferroelectric material is >0.7. The method for preparing the thin films of ferroelectric material comprises providing a precursor solution containing lead, A2+, and B5+; modifying the precursor solution by addition of a polymer species thereto; applying the modified precursor solution to a surface of a substrate and forming a coating thereon; and (d) subjecting the coating to a heat treatment and forming the film in the perovskite phase. Optimal results have been obtained with PEG200 as the polymer species.

Abstract: A Bi-substituted rare earth iron garnet single crystal has a composition of R3-xBixFe5-wAwO12 (wherein R denotes one or more rare earth elements among Tb, Y, Eu, Gd, Ho, Yb, Lu, Nd, Tm, La, Sm, Dy, Er, Ce, and Pr and inevitably include Tb; A denotes one or more elements among Ga, Al, In, Sc, Co, Ni, Cr, V, Ti, Si, Ge, Mg, Zn, Nb, Ta, Sn, Zr, Hf, Pt, Rh, Te, Os, Ce, and Lu, 0.7<x?1.5, and 0<w?1.5), contains Pt and does not contain Pb, and additionally contains Mn or at least one Group 2 element, wherein the coefficient ? is set at a value within a numerical range of 0.91±0.05 and ? (which means [M]?(?×[Pt])) is set from ?7.23 atppm to 1.64 atppm.

Abstract: The present invention can provide an Mg-containing ZnO mixed single crystal wherein the mixed single crystal comprises an Mg-containing ZnO semiconductor having a bandgap (Eg) of 3.30<Eg?3.54 eV, and has a film thickness of 5 ?m or less. The present invention can provide a method for producing an Mg-containing ZnO mixed single crystal by liquid phase epitaxial growth, wherein the method comprises: mixing and melting ZnO and MgO as solutes and PbO and Bi2O3 (or PbF2 and PbO) as solvents; and putting a substrate into direct contact with the obtained melt solution, thereby growing the Mg-containing ZnO mixed single crystal on the substrate.

Abstract: The present invention can provide an Mg-containing ZnO mixed single crystal wherein the mixed single crystal comprises an Mg-containing ZnO semiconductor having a bandgap (Eg) of 3.30?Eg?3.54 eV, and has a film thickness of 5 ?m or less. The present invention can provide a method for producing an Mg-containing ZnO mixed single crystal by liquid phase epitaxial growth, wherein the method comprises: mixing and melting ZnO and MgO as solutes and PbO and Bi2O3 (or PbF2 and PbO) as solvents; and putting a substrate into direct contact with the obtained melt solution, thereby growing the Mg-containing ZnO mixed single crystal on the substrate.

Abstract: In a synthetic method for porous silica crystals through a hydrothermal reaction, a method for synthesizing porous silica crystals with a size of 0.5 mm or larger in high reproducibility and efficiency is provided using a method for manufacturing the porous silica crystals, wherein a high concentration area with silicon is formed as a partial area inside a hydrothermal synthesis vessel, and at least a part of a surface-smoothed bulk material is present in the high concentration area with silicon to perform the hydrothermal reaction, the bulk material comprising a compound containing both silicon and oxygen as a supply source for a part or a whole of the structure composition elements of the porous silica crystals.

Abstract: A method for producing a silicon single crystal in accordance with CZ method, characterized in that before producing the crystal having a predetermined kind and concentration of impurity, another silicon single crystal having the same kind and concentration of impurity as the crystal to be produced is grown to thereby determine an agglomeration temperature zone of grown-in defects thereof, and then based on the temperature, growth condition of the crystal to be produced or temperature distribution within a furnace of a pulling apparatus is set such that a cooling rate of the crystal for passing through the agglomeration temperature zone is a desired rate to thereby produce the silicon single crystal. A silicon single crystal produced in accordance with the above method, characterized in that a density of LSTD before subjecting to heat treatment is 500 number/cm2 or more and the average defect size is 70 nm or less.

Abstract: A process for producing nitrogen-doped semiconductor wafers has the nitrogen being derived from a dopant gas which contains NH3. The process includes pulling a single crystal from a melt of molten semiconductor material, feeding the dopant gas to the semiconductor material, and cutting the nitrogen-doped semiconductor wafers off the pulled single crystal. The dopant gas is fed to the semiconductor material at most until pulling begins for that part of the single crystal from which the semiconductor wafers are cut.

Abstract: A process for producing silicon wafers with low defect density is one wherein a) a silicon single crystal having an oxygen doping concentration of at least 4*10.sup.17 /cm.sup.3 is produced by molten material being solidified to form a single crystal and is then cooled, and the holding time of the single crystal during cooling in the temperature range of from 850.degree. C. to 1100.degree. C. is less than 80 minutes; b) the single crystal is processed to form silicon wafers; and c) the silicon wafers are annealed at a temperature of at least 1000.degree. C. for at least one hour. Also, it is possible to prepare a silicon single crystal based upon having an oxygen doping concentration of at least 4*10.sup.17 /cm.sup.3 and a nitrogen doping concentration of at least 1*10.sup.14 /cm.sup.3 for (a) above.

Abstract: A process for producing optoelectric articles, in which an optoelectric single crystal film is formed on an optoelectric single crystal substrate, is disclosed. The optoelectric single crystal substrate is exposed to a liquid phase in a supercooling state of a melt including a solute and a melting medium, and the optoelectric single crystal film is formed by a liquid phase epitaxial process. In this case, a viscosity of the liquid phase is set to 75%.about.95% preferably 75%.about.90% with respect to a viscosity at which a degree of supercooling of the liquid phase is zero.