A method of manufacturing a semiconductor element includes: forming a first semiconductor layer (SL1) and a second semiconductor layer (SL2) larger in thickness than the first semiconductor layer (SL1) on a mask layer (ML) including a first opening portion (K1) and a second opening portion (K2); forming a first device layer (DL1) and a second device layer (DL2); and bonding the first device layer (DL1) and the second device layer (DL2) to a support substrate (SK).

The present disclosure describes epitaxial oxide high electron mobility transistors (HEMTs). In some embodiments, a HEMT comprises: a substrate; a first epitaxial semiconductor layer on the substrate; and a second epitaxial semiconductor layer on the first epitaxial semiconductor layer. The first epitaxial semiconductor layer can comprise a first oxide material, wherein the first oxide material can comprise a first polar material with an orthorhombic, tetragonal or trigonal crystal symmetry, and wherein the first oxide material can comprise a first conductivity type formed via polarization. The second epitaxial semiconductor layer can comprise a second oxide material.

A nitride semiconductor ultraviolet light-emitting element is provided. The element includes a light-emitting element structure part with an n-type layer, an active layer, and a p-type layer stacked vertically, which are made of AlGaN-based semiconductors with wurtzite structure. The n-type layer has an n-type AlGaN-based semiconductor, the active layer has well layers including an AlGaN based semiconductor, and the p-type layer has a p-type AlGaN-based semiconductor. Each semiconductor layer in the n-type and the active layers is an epitaxially grown layer having a surface on which multi-step terraces parallel to the (0001) plane are formed. The n-type layer has first Ga-rich regions which include n-type AlGaN regions in which an AlGaN composition ratio is an integer ratio of Al.sub.1Ga.sub.1N.sub.2. The well layer includes a second Ga-rich region, which includes an AlGaN region in which an AlGaN composition ratio is an integer ratio of Al.sub.1Ga.sub.2N.sub.3.

An interface including roughness components for improving the propagation of radiation through the interface is provided. The interface includes a first profiled surface of a first layer comprising a set of large roughness components providing a first variation of the first profiled surface having a first characteristic scale and a second profiled surface of a second layer comprising a set of small roughness components providing a second variation of the second profiled surface having a second characteristic scale. The first characteristic scale is approximately an order of magnitude larger than the second characteristic scale. The surfaces can be bonded together using a bonding material, and a filler material also can be present in the interface.

An interface including roughness components for improving the propagation of radiation through the interface is provided. The interface includes a first profiled surface of a first layer comprising a set of large roughness components providing a first variation of the first profiled surface having a first characteristic scale and a second profiled surface of a second layer comprising a set of small roughness components providing a second variation of the second profiled surface having a second characteristic scale. The first characteristic scale is approximately an order of magnitude larger than the second characteristic scale. The surfaces can be bonded together using a bonding material, and a filler material also can be present in the interface.

A display device includes a pixel including a first sub-pixel emitting light of a first color and a second sub-pixel emitting light of a second color. Each of the first sub-pixel and the second sub-pixel includes: a pixel circuit layer disposed on a substrate, the pixel circuit layer including a pixel circuit, and a display element layer disposed on the pixel circuit layer, the display element layer including a light emitting element which includes an anode electrode and a cathode electrode. The pixel circuit layer includes a first contact part disposed between the substrate and the display element layer, the anode electrode and the pixel circuit being connected to each other through the first contact part to supply an anode signal to the light emitting element. A plurality of first contact parts which include a first contact part in the first sub-pixel and a first contact part in the second sub-pixel are arranged along a first direction.

A display device includes: a plurality of pixel electrodes disposed to be spaced apart from each other on a substrate; a plurality of light emitting elements disposed on the plurality of pixel electrodes; a first undoped semiconductor layer on the plurality of light emitting elements; a second undoped semiconductor layer between the first undoped semiconductor layer and the plurality of light emitting elements; and a common electrode layer between the first undoped semiconductor layer and the second undoped semiconductor layer, wherein the common electrode layer includes at least two parts which are separated from each other.

A light emitting diode (LED) device includes a substrate and a plurality of mesa structures. Each mesa structure includes a layer of a first semiconductor material, a porous layer of the first semiconductor material on the layer of the first semiconductor material, and a layer of a second semiconductor material on the porous layer. The porous layer is characterized by an areal porosity ≥15%. The second semiconductor material is characterized by a lattice constant greater than a lattice constant of the first semiconductor material. Each mesa structure also includes an active region on the layer of the second semiconductor material and configured to emit red light, a p-contact layer on the active region, a dielectric layer on sidewalls of the p-contact layer and the active region, and an n-contact layer in physical contact with at least a portion of sidewalls of the layer of the second semiconductor material.

A light emitting diode (LED) device includes a substrate and a plurality of mesa structures. Each mesa structure includes a layer of a first semiconductor material, a porous layer of the first semiconductor material on the layer of the first semiconductor material, and a layer of a second semiconductor material on the porous layer. The porous layer is characterized by an areal porosity ≥15%. The second semiconductor material is characterized by a lattice constant greater than a lattice constant of the first semiconductor material. Each mesa structure also includes an active region on the layer of the second semiconductor material and configured to emit red light, a p-contact layer on the active region, a dielectric layer on sidewalls of the p-contact layer and the active region, and an n-contact layer in physical contact with at least a portion of sidewalls of the layer of the second semiconductor material.

An electroluminescent device comprises a structure comprising a set of nanowires on the surface of a substrate, comprising: a first series of primary so-called emission nanowires (NTi.sub.e) comprising nanowires connected to first electrical contacts and capable of emitting light under the action of a forward first voltage from a forward voltage or current source; a second series of secondary detection nanowires (NTi.sub.d) adjacent to the primary nanowires, connected to second electrical contacts and capable of generating a photocurrent under the action of an ambient light and/or of a portion of the light emitted by some of the primary nanowires, under the control of a second reverse voltage, from a voltage or current source; means for controlling the forward voltage as a function of the photocurrent. A method for controlling the luminance of an electroluminescent device is provided.