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.

Integrated circuitry is fabricated from semiconductor layers formed on a substrate, which include at least one n-type layer, an inverted p-type modulation doped quantum well (mod-doped QW) structure, a non-inverted n-type mod-doped QW structure, and at least one p-type layer including a first P+-type layer formed below a second P-type layer. An etch operation exposes the second p-type layer. P-type ions are implanted into the exposed second p-type layer. A gate electrode of a n-channel HFET device is formed in contact with the p-type ion implanted region. Source and drain electrodes of the n-channel HFET device are formed in contact with n-type ion implanted regions formed in contact with the n-type mod-doped QW structure. P-channel HFET devices, complementary BICFET devices, stacked complementary HFET devices and circuits and/or logic gates based thereon, and a variety of optoelectronic devices and optical devices can also be formed as part of the integrated circuitry.

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.

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.

A method of forming an integrated circuit employs a plurality of layers formed on a substrate including i) bottom n-type ohmic contact layer, ii) p-type modulation doped quantum well structure (MDQWS) with a p-type charge sheet formed above the bottom n-type ohmic contact layer, iii) n-type MDQWS offset vertically above the p-type MDQWS, and iv) etch stop layer formed above the p-type MDQWS. P-type ions are implanted to define source/drain ion-implanted contact regions of a p-channel HFET which encompass the p-type MDQWS. An etch operation removes layers above the etch stop layer of iv) for the source/drain ion-implanted contact regions using an etchant that automatically stops at the etch stop layer of iv). Another etch operation removes remaining portions of the etch stop layer of iv) to form mesas that define an interface to the source/drain ion-implanted contact regions of the p-channel HFET. Source/Drain electrodes are on such mesas.

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 μm, 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 modulation doped semiconductor laser includes a multiple quantum well composed of a plurality of layers including a plurality of first layers and a plurality of second layers stacked alternately and including an acceptor and a donor; a p-type semiconductor layer in contact with an uppermost layer of the plurality of layers; and an n-type semiconductor layer in contact with a lowermost layer of the plurality of layers, the plurality of first layers including the acceptor so that a p-type carrier concentration is 10% or more and 150% or less of the p-type semiconductor layer, the plurality of second layers containing the acceptor so that the p-type carrier concentration is 10% or more and 150% or less of the p-type semiconductor layer, the plurality of second layers containing the donor, and an effective carrier concentration corresponding to a difference between the p-type carrier concentration and an n-type carrier concentration is 10% or less of the p-type carrier concentration of the plurality of second layers.

A method for preparing an erbium (Er)- or erbium oxygen (Er/O)-doped silicon-based luminescent material emitting a communication band at room temperature. The method comprising the following steps: (a) doping a single crystalline silicon wafer with erbium ion implantation or co-doping the single crystalline silicon wafer with erbium ion and oxygen ion implantation simultaneously to obtain an Er- or Er/O-doped silicon wafer, wherein the single crystalline silicon wafer is a silicon wafer with a germanium epitaxial layer, or an SOI silicon wafer with silicon on an insulating layer or other silicon-based wafers; and (b) subjecting the Er- or Er/O-doped silicon wafer to a deep-cooling annealing treatment, the deep-cooling annealing treatment includes a temperature increasing process and a rapid cooling process.

A gain medium for semiconductor optical amplifier in high-power operation includes a substrate with n-type doping; a lower clad layer formed overlying the substrate; a lower optical confinement stack overlying the lower clad layer; an active layer comprising a multi-quantum-well heterostructure with multiple well layers characterized by about 0.8% to 1.2% compressive strain respectively separated by multiple barrier layers characterized by about −0.1% to −0.5% tensile strain. The active layer overlays the lower optical confinement stack. The gain medium further includes an upper optical confinement stack overlying the active layer, the upper optical confinement stack being set thinner than the lower optical confinement stack; an upper clad layer overlying the upper optical confinement stack; and a p-type contact layer overlying the upper clad layer.

The semiconductor laser device includes: an activation layer having at least one first quantum dot layer and at least one second quantum dot layer having a longer emission wavelength than the first quantum dot layer. The gain spectrum of the active layer has the maximum values at the first wavelength and the second wavelength longer than the first wavelength corresponding to the emission wavelength of the first quantum dot layer and the emission wavelength of the second quantum dot layer, respectively. The maximum value of the gain spectrum at the first wavelength is defined as the first maximum value, and the maximum value of the gain spectrum at the second wavelength is defined as the second maximum value. The first maximum value is larger than the second maximum value.