A thermal emission source capable of switching the intensity of light at a high response speed similarly to a photoelectric conversion element. A thermal emission source includes: a two-dimensional photonic crystal including a slab in which an n-layer made of an n-type semiconductor, a quantum well structure layer having a quantum well structure, and a p-layer made of a p-type semiconductor are stacked in the mentioned order in the thickness direction, wherein modified refractive index areas (air holes) whose refractive index differs from the refractive indices of the n-layer, the p-layer and the quantum well structure layer are cyclically arranged in the slab so as to resonate with a specific wavelength of light corresponding to a transition energy between the subbands in a quantum well in the quantum well structure layer; and a p-type electrode and an n-type electrode for applying, to the slab, a voltage which is negative on the side of the p-layer and positive on the side of the n-layer.

A semiconductor device includes a series of layers formed on a substrate, including a first plurality of n-type layers, a second plurality of layers that form a p-type modulation doped quantum well structure (MDQWS), a third plurality of layers disposed between the p-type MDQWS and a fourth plurality of layers that form an n-type MDQWS, and a fifth plurality of p-type layers. The first plurality of layers includes a first etch stop layer of n-type formed on an n-type contact layer. The third plurality of layers includes a second etch stop layer formed above the p-type MDQWS and a third etch stop layer formed above and offset from the second etch stop layer. The fifth plurality of layers includes a fourth etch stop layer of p-type formed above the n-type MDQWS and a fifth etch stop layer of p-type doping formed above and offset from the fourth etch stop 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.

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.

The semiconductor layer sequence includes an n-conductive layer, a p-conductive layer and an active zone located therebetween. The active zone comprises N quantum wells with N2. At a first working point (W1) at a first current density, the quantum wells have a first emission wavelength and, at a second working point (W2) at a second current density, a second emission wavelength. At least two of the first emission wavelengths differ from one another and at least some of the second emission wavelengths differ from the first emission wavelengths. The first current density is smaller than the second current density and the current densities differ from one another at least by a factor of 2.

A semiconductor device includes a semiconductor structure including a first conductive semiconductor layer, a second conductive semiconductor layer disposed on the first conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer. The first conductive semiconductor layer includes a first superlattice layer including a plurality of first sub layers and a plurality of second sub layers, and a first sub layer of the plurality of first sub layers and a second sub layer of the plurality of second sub layers are alternately disposed. The semiconductor structure includes a composition of a first dopant which is a n-type dopant.

A semiconductor device is provided, which includes an epitaxial structure. The epitaxial structure includes a first semiconductor structure, a second semiconductor structure, and an active region. The first semiconductor structure has a first conductivity type and includes a first intermediate layer and a first cladding layer. The second semiconductor structure has a second conductivity type. The active region is located between the first semiconductor structure and the second semiconductor structure. The first intermediate layer is located between the active region and the first cladding layer. The first intermediate layer includes P or As. The first intermediate layer and the first cladding layer include a first dopant. A maximum concentration of the first dopant in the first intermediate layer is greater than a maximum concentration of the first dopant in the first cladding 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.

An optical semiconductor device includes an active layer having a plurality of quantum dot layers. The plurality of quantum dot layers includes at least one quantum dot player doped with a p-type impurity. Further, the plurality of quantum dot layers includes at least two quantum dot layers having different emission wavelengths and different p-type impurity concentrations.

Hybrid III-V silicon device structures including a silicon optical waveguide of a first width, a III-V semiconductor mesa of a second width and a current channel of a third width that is smaller than the second width. The third width may be only slightly larger than the first width to narrowly confine electrical current directly over the optical waveguide while the second width is significantly larger than the first width to efficiently transport heat away from the optical gain medium. The current channel has low electrical resistivity and one or more material layers within the mesa are converted to a compound comprising aluminum (Al) and oxygen (O) having higher electrical resistivity. A mesa may be fabricated from a III-V material stack comprising one or more Al-rich layers, which are preferentially oxidized to form resistive aluminum oxide regions that laterally encroach a center of the mesa where current is confined.