A layer of a crystal of a group 13 nitride selected from gallium nitride, aluminum nitride, indium nitride and the mixed crystals thereof has an upper surface and a bottom surface. The upper surface includes a linear high-luminance light-emitting part and a low-luminance light-emitting region adjacent to the high-luminance light-emitting part. The high-luminance light-emitting part includes a portion extending along an m-plane of the crystal of the group 13 nitride. A normal line to the upper surface has an off-angle of 2.0° or less with respect to <0001> direction of the crystal of the nitride of the group 13 element.

The present disclosure provides a growth method of a high-temperature phase lanthanum borosilicate crystal, where the high-temperature phase lanthanum borosilicate crystal is a β-La.sub.1-yLn.sub.yBSiO.sub.5 crystal prepared by a high-temperature flux method; a composite flux system is (La.sub.1-yLn.sub.y)BO.sub.3—LiMoO.sub.4—SiO.sub.2—B.sub.2O.sub.3, and (La.sub.1-yLn.sub.y)BO.sub.3, LiMoO.sub.4, SiO.sub.2, and B.sub.2O.sub.3 in the system have molar percentages of x.sub.1, x.sub.2, x.sub.3, and x.sub.4, respectively; 0<x.sub.1<0.3, 0.7≤x.sub.2<1, 0<x.sub.3<0.3, x.sub.1+x.sub.2+x.sub.3=1, x.sub.1:x.sub.4=2:1 to 4:1. In the present disclosure, a difficulty is overcome in the crystal growth of β-LaBSiO.sub.5 due to phase transition. The crystal is an optical function material that does not undergo the phase transition during annealing and can exist stably at room temperature. The crystal is widely used in laser, terahertz, and other fields.

There is provided a Group-III element nitride semiconductor substrate including a first surface and a second surface, in which even when devices to be produced on the first surface are increased in size, variations in device characteristics between the devices in the same substrate are suppressed. A Group-III element nitride semiconductor substrate includes a first surface and a second surface. The Group-III element nitride semiconductor substrate satisfies at least one of the following items (1) to (3): (1) The main surface has a maximum height Wz of a surface waviness profile of 150 nm or less; (2) The main surface has a root mean square height Wq of the surface waviness profile of 25 nm or less; (3) The main surface has an average length WSm of surface waviness profile elements of 0.5 mm or more.

The invention refers to a composite wavelength converter (1) for an LED (100), comprising a substrate (10) and an epitaxial film (20) formed by liquid phase epitaxy on the top and bottom of the substrate (10). Furthermore, the invention refers to a method of preparation of a composite wavelength converter (1) for an LED (100). Furthermore, the invention refers to a white LED light source comprising an LED (100) and an inventive composite wavelength converter (1) mounted on a light emitting surface of the LED (100).

A crystal substrate 1 includes an underlying layer 2 and a thick film 3. The underlying layer 2 is composed of a crystal of a nitride of a group 13 element and includes a first main face 2a and a second main face 2b. The thick film 3 is composed of a crystal of a nitride of a group 13 element and provided over the first main face of the underlying layer. The underlying layer 2 includes a low carrier concentration region 5 and a high carrier concentration region 4 both extending between the first main face 2a and the second main face 2b.

A crystal substrate 1 includes an underlying layer 2 and a thick film 3. The underlying layer 2 is composed of a crystal of a nitride of a group 13 element and includes a first main face 2a and a second main face 2b. The thick film 3 is composed of a crystal of a nitride of a group 13 element and provided over the first main face of the underlying layer. The underlying layer 2 includes a low carrier concentration region 5 and a high carrier concentration region 4 both extending between the first main face 2a and the second main face 2b.

A free-standing substrate, for growing epitaxial crystal composed of a group 13 nitride crystal selected from gallium nitride, aluminum nitride, indium nitride or a mixed crystal thereof, includes a nitrogen polar surface and group 13 element polar surface. The nitrogen polar surface is warped in a convex shape, and a chamfer part is provided in an outer peripheral part of the nitrogen polar surface.

The present invention provides a PZN-based large-size ternary high-performance single crystal, a growing method and a molten salt furnace. The PZN-based large-size ternary high-performance single crystal is represented by formula (1-x-y)Pb(B′.sub.1/2B″.sub.1/2)O.sub.3-yPb(Zn.sub.1/3Nb.sub.2/3)O.sub.3-xPbTiO.sub.3, wherein B′ is Mg, Fe, Sc, Ni, In, Yb, Lu and/or Ho, B″ is Nb, Ta and/or W, 0.4<x<0.6, 0.1<y<0.4, 0.1<1-x-y<0.4. The present invention adjusts the convective change of the melt through the rotation of the top seed and the bottom crucible, overcoming the problems of serious crystal inclusions and poor crystal quality during the growth process, and can adapt the change of the crystal diameter to the thermal inertia of the heat preservation system, thus effectively reducing crystal inclusions and improving the yield of the crystal.

A seed crystal layer is provided on a supporting body. A laser light is irradiated from a side of the supporting body to provide an altered portion along an interface between the supporting body and seed crystal layer. The altered layer is composed of a nitride of a group 13 element and comprising a portion into which dislocation defects are introduced or an amorphous portion.

The present invention provides a method for producing a Group III nitride crystal, capable of producing a Group III nitride crystal in a large size with few defects and high quality. The method is a method for producing a Group III nitride crystal (13), including: a seed crystal selection step of selecting plural parts of a Group III nitride crystal layer (11) as seed crystals for generation and growth of Group III nitride crystals (13); a contact step of causing the surfaces of the seed crystals to be in contact with an alkali metal melt; a crystal growth step of causing a Group III element and nitrogen to react with each other under a nitrogen-containing atmosphere in the alkali metal melt to generate and grow the Group III nitride crystals (13), wherein the seed crystals are hexagonal crystals, in the seed crystal selection step, the seed crystals are arranged so that m-planes of the respective crystals grown from the seed crystals that are adjacent to each other do not substantially coincide with each other, and in the crystal growth step, the plural Group III nitride crystals (13) grown from the plural seed crystals by the growth of the Group III nitride crystals (13) are bound.