A method of manufacturing a light-emitting device includes: providing a substrate; forming a light-emitting structure comprising an active layer on the substrate; forming a protective layer having a first thickness on the light-emitting structure; etching the protective layer such that the protective layer has a second thickness less than the first thickness; and patterning the protective layer.

Heterostructures include a layer of a two-dimensional material placed on a multiferroic layer. An ordered array of differing polarization domains in the multiferroic layer produces corresponding domains having differing properties in the two-dimensional material. When the multiferroic layer is ferroelectric, the ferroelectric polarization domains in the layer produce local electric fields that penetrate the two-dimensional material. The local electric fields modulate the charge carriers and carrier density on a nanometer length scale, resulting in the formation of lateral p-n or p-i-n junctions, and variations thereof appropriate for device functions.

In some embodiments, a semiconductor structure includes: a first epitaxial oxide semiconductor layer; a metal layer; and a contact layer adjacent to the metal layer, and between the first epitaxial oxide semiconductor layer and the metal layer. The contact layer can include an epitaxial oxide semiconductor material. The contact layer can also include a region comprising a gradient in a composition of the epitaxial oxide semiconductor material adjacent to the metal layer, or a gradient in a strain of the epitaxial oxide semiconductor material over a region adjacent to the metal layer.

A method for growing a transition metal dichalcogenide layer involves arranging a substrate having a first transition metal contained pad is arranged in a chemical vapor deposition chamber. A chalcogen contained precursor is arranged upstream of the substrate in the chemical vapor deposition chamber. The chemical vapor deposition chamber is heated for a period of time during which a transition metal dichalcogenides layer, containing transition metal from the first transition metal contained pad and chalcogen from the chalcogen contained precursor, is formed in an area adjacent to the first transition metal contained pad.

A substrate comprising a III-N base layer comprising a first portion and a second portion, the first portion of the III-N base layer having a first natural lattice constant and a first dislocation density; and a first III-N layer having a second natural lattice constant and a second dislocation density on the III-N base layer, the first III-N layer having a thickness greater than 10 nm. An indium fractional composition of the first III-N layer is greater than 0.1; the second natural lattice constant is at least 1% greater than the first natural lattice constant; a strain-induced lattice constant of the first III-N layer is greater than 1.0055 times the first natural lattice constant; and the second dislocation density is less than 1.5 times the first dislocation density.

Disclosed are a quantum light source and an optical communication apparatus including the same. The quantum light source device includes a vertical reflection layer disposed on a substrate, a lower electrode layer disposed on the vertical reflection layer, a horizontal reflection layer disposed on the lower electrode layer, a quantum light source disposed in the horizontal reflection layer, and an upper electrode layer disposed on the horizontal reflection layer.

A nitride semiconductor structure includes a Group III nitride semiconductor portion and a Group II-IV nitride semiconductor portion. The Group III nitride semiconductor portion is single crystalline. The Group III nitride semiconductor portion has a predetermined crystallographic plane. The Group II-IV nitride semiconductor portion is provided on the predetermined crystallographic plane of the Group III nitride semiconductor portion. The Group II-IV nitride semiconductor portion is single crystalline. The Group II-IV nitride semiconductor portion contains a Group II element and a Group IV element. The Group II-IV nitride semiconductor portion forms a heterojunction with the Group III nitride semiconductor portion. The predetermined crystallographic plane is a crystallographic plane other than a (0001) plane.

A semiconductor structure can include a substrate comprising a first in-plane lattice constant, a graded layer on the substrate, and a first region of the graded layer comprising a first epitaxial oxide material comprising a second in-plane lattice constant. The graded layer on the substrate can include (Al.sub.x1Ga.sub.1−x1).sub.y1O.sub.z1, wherein x1 is from 0 to 1, wherein y1 is from 1 to 3, wherein z1 is from 2 to 4, and wherein x1 varies in a growth direction such that the graded layer has the first in-plane lattice constant adjacent to the substrate and a second in-plane lattice constant at a surface of the graded layer opposite the substrate. In some cases, a semiconductor structure includes a first region comprising a first epitaxial oxide material; a second region comprising a second epitaxial oxide material; and the graded region located between the first and the second regions.

The present disclosure describes epitaxial oxide field effect transistors (FETs). In some embodiments, a FET comprises: a substrate comprising an oxide material; an epitaxial semiconductor layer on the substrate; a gate layer on the epitaxial semiconductor layer; and electrical contacts. In some cases, the epitaxial semiconductor layer can comprise a superlattice comprising a first and a second set of layers comprising oxide materials with a first and second bandgap. The gate layer can comprise an oxide material with a third bandgap, wherein the third bandgap is wider than the first bandgap. In some cases, the epitaxial semiconductor layer can comprise a second oxide material with a first bandgap, wherein the second oxide material comprises single crystal A.sub.xB.sub.1-xO.sub.n, wherein 0<x<1.0, wherein A is Al and/or Ga, wherein B is Mg, Ni, a rare earth, Er, Gd, Ir, Bi, or Li.

An improved heterostructure for an optoelectronic device is provided. The heterostructure includes an active region, an electron blocking layer, and a p-type contact layer. The heterostructure can include a p-type interlayer located between the electron blocking layer and the p-type contact layer. In an embodiment, the electron blocking layer can have a region of graded transition. The p-type interlayer can also include a region of graded transition.