A vapor phase epitaxy method of growing a III-V layer with a doping that changes from a first conductivity type to a second conductivity type on a surface of a substrate or a preceding layer in a reaction chamber from the vapor phase from an epitaxial gas flow comprising a carrier gas, at least one first precursor for an element from main group III, and at least one second precursor for an element from main group V, wherein when a first growth height is reached, a first initial doping level of the first conductivity type is set by means of a ratio of a first mass flow of the first precursor to a second mass flow of the second precursor in the epitaxial gas flow, the first initial doping level is then reduced to a second initial doping level of the first or low second conductivity type.

A method for manufacturing nitride catalyst is provided, which includes putting a Ru target and an M target into a nitrogen-containing atmosphere, in which M is Ni, Co, Fe, Mn, Cr, V, Ti, Cu, or Zn. The method also includes providing powers to the Ru target and the M target, respectively. The method also includes providing ions to bombard the Ru target and the M target for depositing M.sub.xRu.sub.yN.sub.2 on a substrate by sputtering, wherein 0<x<1.3, 0.7<y<2, and x+y=2, wherein M.sub.xRu.sub.yZ.sub.2 is cubic crystal system or amorphous.

A method for manufacturing nitride catalyst is provided, which includes putting a Ru target and an M target into a nitrogen-containing atmosphere, in which M is Ni, Co, Fe, Mn, Cr, V, Ti, Cu, or Zn. The method also includes providing powers to the Ru target and the M target, respectively. The method also includes providing ions to bombard the Ru target and the M target for depositing M.sub.xRu.sub.yN.sub.2 on a substrate by sputtering, wherein 0<x<1.3, 0.7<y<2, and x+y=2, wherein M.sub.xRu.sub.yZ.sub.2 is cubic crystal system or amorphous.

The present invention provides an epitaxial film forming method for epitaxially growing a high-quality group III nitride semiconductor thin film on an -Al.sub.2O.sub.3 substrate by a sputtering method. In the epitaxial film forming method according to an embodiment of the present invention, when an epitaxial film of a group III nitride semiconductor thin film is to be formed on the -Al.sub.2O.sub.3 substrate arranged on a substrate holder provided with a heater electrode and a bias electrode of a sputtering apparatus, in a state where the -Al.sub.2O.sub.3 substrate is maintained at a predetermined temperature by the heater electrode, high-frequency power is applied to a target electrode and high-frequency bias power is applied to a bias electrode and at that time, the powers are applied so that frequency interference between the high-frequency power and the high-frequency bias power does not occur.

The present invention provides an epitaxial film forming method for epitaxially growing a high-quality group III nitride semiconductor thin film on an -Al.sub.2O.sub.3 substrate by a sputtering method. In the epitaxial film forming method according to an embodiment of the present invention, when an epitaxial film of a group III nitride semiconductor thin film is to be formed on the -Al.sub.2O.sub.3 substrate arranged on a substrate holder provided with a heater electrode and a bias electrode of a sputtering apparatus, in a state where the -Al.sub.2O.sub.3 substrate is maintained at a predetermined temperature by the heater electrode, high-frequency power is applied to a target electrode and high-frequency bias power is applied to a bias electrode and at that time, the powers are applied so that frequency interference between the high-frequency power and the high-frequency bias power does not occur.

Growth of single crystal epitaxial films of the perovskite crystal structure by liquid- or vapor-phase means can be accomplished by providing single-crystal perovskite substrate materials of improved lattice parameter match in the lattice parameter range of interest. Current substrates do not provide as good a lattice match, have inferior properties, or are of limited size and availability because cost of materials and difficulty of growth. This problem is solved by the single-crystal perovskite solid solutions described herein grown from mixtures with an indifferent melting point that occurs at a congruently melting composition at a temperature minimum in the melting curve in the pseudo-binary molar phase diagram. Accordingly, single-crystal perovskite solid solutions, structures, and devices including single-crystal perovskite solid solutions, and methods of making single-crystal perovskite solid solutions are described herein.

Growth of single crystal epitaxial films of the perovskite crystal structure by liquid- or vapor-phase means can be accomplished by providing single-crystal perovskite substrate materials of improved lattice parameter match in the lattice parameter range of interest. Current substrates do not provide as good a lattice match, have inferior properties, or are of limited size and availability because cost of materials and difficulty of growth. This problem is solved by the single-crystal perovskite solid solutions described herein grown from mixtures with an indifferent melting point that occurs at a congruently melting composition at a temperature minimum in the melting curve in the pseudo-binary molar phase diagram. Accordingly, single-crystal perovskite solid solutions, structures, and devices including single-crystal perovskite solid solutions, and methods of making single-crystal perovskite solid solutions are described herein.

Organic-inorganic hybrid perovskite has demonstrated tremendous potential for the next generation of electronic and optoelectronic devices due to their remarkable carrier dynamics. However, current studies of electronic and optoelectronic devices have been focused on polycrystalline materials, due to the challenges in synthesizing device compatible high quality single crystalline materials. Here, we firstly report the epitaxial growth of single crystal hybrid perovskites with controlled locations, morphologies, and orientations, using combined strategies of lithography, homoepitaxy, and low temperature solution method. The crystals grow following a layer-by-layer model under controlled growth parameters. The process is robust and can be readily scaled up. The as-grown epitaxial single crystals were integrated in an array of light emitting diodes, each crystal as a pixel with enhanced quantum efficiencies. This capability opens up new opportunities for designing and fabricating a diverse range of high performance electronic and optoelectronic devices using crystalline hybrid perovskites.

Organic-inorganic hybrid perovskite has demonstrated tremendous potential for the next generation of electronic and optoelectronic devices due to their remarkable carrier dynamics. However, current studies of electronic and optoelectronic devices have been focused on polycrystalline materials, due to the challenges in synthesizing device compatible high quality single crystalline materials. Here, we firstly report the epitaxial growth of single crystal hybrid perovskites with controlled locations, morphologies, and orientations, using combined strategies of lithography, homoepitaxy, and low temperature solution method. The crystals grow following a layer-by-layer model under controlled growth parameters. The process is robust and can be readily scaled up. The as-grown epitaxial single crystals were integrated in an array of light emitting diodes, each crystal as a pixel with enhanced quantum efficiencies. This capability opens up new opportunities for designing and fabricating a diverse range of high performance electronic and optoelectronic devices using crystalline hybrid perovskites.

A composite nitride-based film structure includes a bulk single crystal, a plurality of nitride microcrystals, and an amorphous nitride thin film. The plurality of nitride microcrystals is provided on the bulk single crystal, and has a specific orientation relationship with a crystal structure of the bulk single crystal. The nitride thin film is provided on the bulk single crystal, surrounds the nitride microcrystal, and covers a surface of the bulk single crystal.