The light emitting device includes a substrate, and a laminated structure provided to the substrate, and including a plurality of columnar parts, wherein the columnar part includes a first semiconductor layer, a second semiconductor layer different in conductivity type from the first semiconductor layer, and a light emitting layer disposed between the first semiconductor layer and the second semiconductor layer, the laminated structure includes a third semiconductor layer which is connected to an opposite side to the substrate of the second semiconductor layer, and is same in conductivity type as the second semiconductor layer, the second semiconductor layer is disposed between the light emitting layer and the third semiconductor layer, the third semiconductor layer is provided with a recessed part, an opening of the recessed part is provided to a surface at an opposite side to the substrate side of the third semiconductor layer, and a diametrical size in a bottom of the recessed part is smaller than a diametrical size in the opening of the recessed part.

A semiconductor laser includes: a multi-quantum well layer in a mesa structure; a buried layer comprising a semi-insulating semiconductor, the buried layer being in contact with each of both sides of the mesa structure; a first cladding layer with a first conductivity type, the first cladding layer having a lower refractive index than the multi-quantum well layer; a high refractive index layer configured to not absorb light oscillating in the multi-quantum well layer, the high refractive index layer having a higher refractive index than the first cladding layer; a diffraction grating layer at least partially constituting a diffraction grating capable of diffracting the light oscillating in the multi-quantum well layer, the diffraction grating layer not contacting the high refractive index layer; a substrate with the first conductivity type; and a second cladding layer with a second conductivity type above the multi-quantum well layer.

A semiconductor laser device includes a first conductivity type cladding layer having a refractive index n.sub.c1, a first conductivity type side optical guide layer, an active layer, a second conductivity type side optical guide layer, and a second conductivity type cladding layer of n.sub.c2 laminated in order on a first conductivity type semiconductor substrate, wherein an oscillation wavelength is λ, a first conductivity type low refractive index layer of n.sub.1 lower than n.sub.c1 having a thickness of d.sub.1 is provided between the first conductivity type side optical guide layer and the first conductivity type cladding layer, a second conductivity type low refractive index layer of n.sub.2 lower than n.sub.c2 having a thickness of d.sub.2 is provided between the second conductivity type side optical guide layer and the second conductivity type cladding layer, and a condition of a normalization frequency v.sub.2>v.sub.1 is satisfied.

A quantum-cascade laser element includes: a semiconductor substrate; a semiconductor laminate formed on the semiconductor substrate to include a ridge portion configured to include an active layer having a quantum-cascade structure; an embedding layer including a first portion formed on a side surface of the ridge portion, and a second portion extending from an edge portion of the first portion on a side of the semiconductor substrate along a width direction of the semiconductor substrate; a metal layer formed on a top surface of the ridge portion, on the first portion, and on the second portion; and a dielectric layer disposed between the second portion and the metal layer. The dielectric layer is formed such that a part of the second portion is exposed from the dielectric layer. The metal layer is in contact with the second portion at the part.

A vehicle component, and a method and tool for forming the component are provided. First and second tools with first and second surfaces, respectively, are provided. The first tool is translated along a first axis towards the second tool such that the first and second surfaces cooperate to define a mold cavity configured to form an accessory mount feature with an aperture. The second surface is configured to form an integrated rib extending outwardly from an upper surface of the mount feature to a planar bearing surface surrounding the aperture with the planar bearing surface oriented at an acute angle relative to the upper surface. The first axis is substantially parallel to the upper surface.

In an embodiment a semiconductor laser diode includes a semiconductor layer sequence comprising an active layer having a main extension plane, the semiconductor layer sequence configured to generate light in an active region and radiate the light via a light-outcoupling surface, wherein the active region extends from a rear surface opposite the light-outcoupling surface to the light-outcoupling surface along a longitudinal direction in the main extension plane and a continuous contact structure directly disposed on a surface of the semiconductor layer sequence, wherein the contact structure comprises in at least a first contact region a first electrical contact material in direct contact with the surface region and in at least a second contact region a second electrical contact material in direct contact with the surface region, wherein the first and second contact regions adjoin one another.

A laser diode (1) includes an AlN single crystal substrate (11), an n-type cladding layer (12) formed on the substrate and including a nitride semiconductor layer having n-type conductivity, a light-emitting layer (14) formed on the n-type cladding layer and including one or more quantum wells, a p-type cladding layer (20) formed on the light-emitting layer and including a nitride semiconductor layer having p-type conductivity, and a p-type contact layer (18) formed on the p-type cladding layer and including a nitride semiconductor that includes GaN. The p-type cladding layer includes a p-type longitudinal conduction layer (16) that includes Al.sub.sGa.sub.1−sN (0.3≤s≤1), has a composition gradient such that the Al composition s decreases with increased distance from the substrate, and has a film thickness of less than 0.5 μm, and a p-type transverse conduction layer (17) that includes Al.sub.tGa.sub.1−tN (0<t≤1).

There are included: a second semiconductor layer of a second conduction-type formed to be on and in contact with the active layer; and a third semiconductor layer of a second conduction-type formed on the second semiconductor layer, the third semiconductor layer is arranged above a formation region of the active layer, a bottom surface of the third semiconductor layer is arranged in the formation region of the active layer, and a width of the third semiconductor layer, on the active layer side, in a direction perpendicular to a waveguide direction and parallel to a plane of a substrate is set to be smaller than a width of the active layer in the same direction.

A quantum-cascade laser element includes: a semiconductor substrate; a semiconductor mesa formed on the semiconductor substrate to include an active layer having a quantum-cascade structure and to extend along a light waveguide direction; an embedding layer formed to interpose the semiconductor mesa along a width direction of the semiconductor substrate; a cladding layer formed over the semiconductor mesa and over the embedding layer; and a metal layer formed on the cladding layer. A pair of groove portions extending along the light waveguide direction are formed in a surface on an opposite side of the cladding layer from the semiconductor substrate. The pair of groove portions are disposed in two respective outer regions when the cladding layer is equally divided into four regions in the width direction of the semiconductor substrate. The metal layer enters the pair of groove portions.

Novel ICL layering designs, ridge waveguide architectures, and processing protocols that will significantly lower the optical losses and improve the power conversion efficiencies of interband cascade lasers designed for both DFB single-mode and high-power applications. The semiconductor top cladding and metal contact layers are eliminated or significantly reduced. By instead using a dielectric or air top clad, or dielectric or air layers to supplement a thin top clad, in conjunction with lateral current injection and weak index-guiding, the present invention will substantially reduce the internal loss of such ICLs, resulting in lower lasing threshold, higher efficiency, and higher maximum power.