A vertical-cavity surface-emitting laser (VCSEL) including a lower mirror, an upper mirror having an insulation region including implanted ions and an isolation region surrounded by the insulation region, an active layer interposed between the lower mirror and the upper mirror, an aperture forming layer interposed between the upper mirror and the active layer, and including an oxidation layer and a window layer surrounded by the oxidation layer, and a plurality of oxidation holes disposed in the isolation region and passing through the upper mirror and the aperture forming layer.

Photonic devices having a photonic waveguiding layer, and a cladding layer, disposed on the photonic waveguiding layer, and where the cladding section is a material comprising Scandium. The cladding layer may include a material comprising Al.sub.1-xSc.sub.xN material where 0<x≤0.45.

Photonic devices having a quantum well structure that includes a Group III-N material, and a Al.sub.1-xSc.sub.xN cladding layer disposed on the quantum well structure, where 0<x≤0.45, the Al.sub.1-xSc.sub.xN cladding layer having a lower refractive index than the index of refraction of the quantum well structure.

Disclosed herein is a semiconductor device comprising: a silicon substrate; a germanium layer; and a buffer layer comprised of at least one layer of III-V compound, formed directly on silicon; at least one layer containing III-V compound quantum dots wherein one or more facets are formed using focused ion beam etching such that the angle between the plane of the facet is normal to the plane of growth.

A surface emitting laser includes: a semiconductor layer containing a nitride semiconductor, and including a first semiconductor layer, an active layer, and a second semiconductor layer that are stacked in this order, in which the semiconductor layer includes a light emitting region; and a first light reflecting layer and a second light reflecting layer that are opposed to each other with the semiconductor layer being disposed therebetween. The first semiconductor layer has a high dislocation portion disposed outside the light emitting region. The high dislocation portion has an average dislocation density higher than an average dislocation density of the light emitting region.

A semiconductor laser element includes an n-side semiconductor layer, an active layer, and a p-side semiconductor layer. A least a portion of the p-side semiconductor layer forms a ridge projecting upward. The p-side semiconductor layer includes an undoped first part, an electron barrier layer containing a p-type impurity and having a larger band gap energy than the first part, and a second part having at least one p-type semiconductor layer. The first part includes an undoped p-side composition graded layer in which a band gap energy increases towards the electron barrier layer, and an undoped p-side intermediate layer disposed on or above the p-side composition graded layer. A lower end of the ridge is positioned at the p-side intermediate layer.

A laser diode including a double heterostructure comprising a top layer, a buffer layer formed on a substrate, and an intrinsic active layer formed between the top layer and the buffer layer. The top layer and the buffer layer have opposite types of conductivity. The active layer has a bandgap smaller than that of the buffer layer or the top layer. The double heterostructure includes Ge, SiGe, GeSn, and/or SiGeSn materials.

A light-emitting device includes: a substrate; a laminated structure provided at the substrate and having a plurality of columnar parts; and an electrode provided on a side opposite to a side of the substrate, of the laminated structure. The columnar part has: a first semiconductor layer; a second semiconductor layer having a different electrical conductivity type from the first semiconductor layer; and an active layer provided between the first semiconductor layer and the second semiconductor layer. The laminated structure has: a light propagation layer provided between the active layers of the columnar parts that are next to each other; a first low-refractive-index part provided between the light propagation layer and the substrate and having a lower refractive index than a refractive index of the light propagation layer; and a second low-refractive-index part provided between the light propagation layer and the electrode and having a lower refractive index than the refractive index of the light propagation layer.

A laser diode is provided, including at least a defect blocking layer deposited between the GaAs substrate and the active layer, so that the crystal defects of the GaAs substrate can be blocked or reduced from propagation to the active layer when the epitaxial layer is formed on the GaAs substrate. As such, the crystal quality of the active layer can be improved, thereby improving the reliability and optical property of the laser diode.

Included is a semiconductor multilayer film in which a non-doped InAlN layer and a GaN layer formed on said InAlN layer and containing a dopant are stacked a plurality of times.