A heterostructure for use in an electronic or optoelectronic device is provided. The heterostructure includes one or more semiconductor layers containing columnar nanostructures (e.g., nanowires). The nanowire semiconductor layer can include sub-layers of varying composition, at least one of which is an active layer that can include quantum wells and barriers. A heterostructure can include n-type and p-type semiconductor contact layers adjacent to the nanowire semiconductor layer containing the active layer.

A germanium waveguide is formed from a P-type silicon substrate that is coated with a heavily-doped N-type germanium layer and a first N-type doped silicon layer. Trenches are etched into the silicon substrate to form a stack of a substrate strip, a germanium strip, and a first silicon strip. This structure is then coated with a silicon nitride layer.

A GaN-based VCSEL chip based on porous DBR and a manufacturing method of the same, wherein the chip includes: a substrate; a buffer layer formed on the substrate; a bottom porous DBR layer formed on the buffer layer; an n-type doped GaN layer formed on the bottom porous DBR layer, which is etched downward on its periphery to form a mesa; an active layer formed on the n-type doped GaN layer; an electron blocking layer formed on the active layer; a p-type doped GaN layer formed on the electron blocking layer; a current limiting layer formed on the p-type doped GaN layer with a current window formed at a center thereof, wherein the current limiting layer covers sidewalls of the active layer, the electron blocking layer and the convex portion of the n-type doped GaN layer; a transparent electrode formed on the p-type doped GaN layer; an n-electrode formed on the mesa of the n-type doped GaN layer; a p-electrode formed on the transparent electrode with a recess formed therein; and a dielectric DBR layer formed on the transparent electrode in the recess of the p-electrode.

In a method for electrically doping a semiconducting material, a layer of germanium is formed having a germanium layer thickness, while in situ incorporating phosphorus dopant atoms at a concentration of at least about 510.sup.18 cm.sup.3 through the thickness of the germanium layer during formation of the germanium layer. Additional phosphorus dopant atoms are ex situ incorporated through the thickness of the germanium layer, after formation of the germanium layer, to produce through the germanium layer thickness a total phosphorus dopant concentration of at least about 210.sup.19 cm.sup.3.

In a semiconductor laser according to an embodiment of the present disclosure, a ridge part has a structure in which a plurality of gain regions and a plurality of Q-switch regions are each disposed alternately with each of separation regions being interposed therebetween in an extending direction of the ridge part. The separation regions each have a separation groove that separates from each other, by a space, the gain region and the Q-switch region adjacent to each other. The separation groove has a bottom surface at a position, in a second semiconductor layer, higher than a part corresponding to a foot of each of both sides of the ridge part.

Embodiments of the invention include a III-nitride light emitting layer disposed between an n-type region and a p-type region, a III-nitride layer including a nanopipe defect, and a nanopipe terminating layer disposed between the III-nitride light emitting layer and the III-nitride layer comprising a nanopipe defect. The nanopipe terminates in the nanopipe terminating layer.

A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm.sup.3 for the intended crystal growth.

A light emitting device includes a substrate, and a laminate provided to the substrate and including a plurality of columnar portions, where each of the columnar portions includes a first semiconductor layer, a second semiconductor layer different in conductivity type from the first semiconductor layer, and a light emitting layer provided between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer includes a facet surface, a c surface, and an m surface, the light emitting layer includes a facet surface region provided to the facet surface, and a c surface region provided to the c surface, the light emitting layer does not include a region provided to the m surface, and the c surface region is larger than the facet surface region in a plan view as viewed from a laminating direction of the laminate.

In an example, the present invention provides a method for fabricating a light emitting device configured as a Group III-nitride based laser device. The method also includes forming a gallium containing epitaxial material overlying the surface region of a substrate member. The method includes forming a p-type (Al,In,Ga)N waveguiding material overlying the gallium containing epitaxial material under a predetermined process condition. The method includes maintaining the predetermined process condition such that an environment surrounding a growth of the p-type (Al,In,Ga)N waveguide material is substantially a molecular N.sub.2 rich gas environment. The method includes maintaining a temperature ranging from 725 C to 925 C during the formation of the p-type (Al,In,Ga)N waveguide material, although there may be variations. In an example, the predetermined process condition is substantially free from molecular H.sub.2 gas.

Provided is a laser device according to an embodiment of the inventive concept. The laser device includes: a semiconductor substrate; a germanium single crystal layer on the semiconductor substrate; and a pumping light source disposed on the germanium single crystal layer and configured to emit light toward the germanium single crystal layer, wherein the germanium single crystal layer receives the light to thereby output laser.