Abstract: An integrated semiconductor optical device and an optical module capable of the high-speed and large-capacity optical transmission are provided. In an integrated semiconductor optical device in which a plurality of optical devices buried with semi-insulating semiconductor materials are integrated on the same semiconductor substrate and an optical module using the integrated semiconductor optical device, configurations (material and electrical characteristics) of the buried layers are made different for each of the optical devices.

Abstract: In an InGaN-based nitride semiconductor optical device having a long wavelength (440 nm or more) equal to or more than that of blue, the increase of a wavelength is realized while suppressing In (Indium) segregation and deterioration of crystallinity. In the manufacture of an InGaN-based nitride semiconductor optical device having an InGaN-based quantum well active layer including an InGaN well layer and an InGaN barrier layer, a step of growing the InGaN barrier layer includes: a first step of adding hydrogen at 1% or more to a gas atmosphere composed of nitrogen and ammonia and growing a GaN layer in the gas atmosphere; and a second step of growing the InGaN barrier layer in a gas atmosphere composed of nitrogen and ammonia.

Abstract: A super-lattice structure is used for a portion of a laser device of a self-aligned structure to lower the resistance of the device by utilizing the extension of electric current in the layer, paying attention to the fact that the lateral conduction of high density doping in the super-lattice structure is effective for decreasing the resistance of the laser, in order to lower the operation voltage and increase the power in nitride type wide gap semiconductor devices in which crystals with high carrier density are difficult to obtain and the device resistance is high.

Abstract: The present invention provides a Be-based group II-VI semiconductor laser using an InP substrate and having a stacked structure capable of continuous oscillation at a room temperature. A basic structure of a semiconductor laser is constituted by using a Be-containing lattice-matched II-VI semiconductor above an InP substrate. An active laser, an optical guide layer, and a cladding layer are constituted in a double hetero structure having a type I band line-up in order to enhance the injection efficiency of carriers to the active layer. Also, the active layer, the optical guide layer, and the cladding layer, which are capable of enhancing the optical confinement to the active layer, are constituted, and the cladding layer is constituted with bulk crystals.

Abstract: A nitride semiconductor laser which features low resistance and high reliability. A buried layer is formed by selective growth and the shape of a p-type cladding layer is inverted trapezoidal so that the resistance of the p-type cladding layer and that of a p-type contact layer are decreased. For long-term reliability of the laser, the buried layer is a high-resistance semi-insulating layer which suppresses increase in leak current.

Abstract: There is disclosed a Be-containing II-VI group semiconductor laser that has a laminated structure formed on an InP substrate to continuously emit at room temperature without crystal degradation. A basic structure of the semiconductor laser is formed over the InP substrate by use of a lattice-matched II-VI group semiconductor including Be. An active layer and cladding layers are formed to be a double heterostructure with a type I band lineup, in order to increase the efficiency for injecting carriers into the active layer. The active layer and the cladding layers are also formed to enhance the light confinement to the active layer, in which the Mg composition of the p-type cladding layer is set to Mg<0.2.

Abstract: A nitride semiconductor laser which features low resistance and high reliability. A buried layer is formed by selective growth and the shape of a p-type cladding layer is inverted trapezoidal so that the resistance of the p-type cladding layer and that of a p-type contact layer are decreased. For long-term reliability of the laser, the buried layer is a high-resistance semi-insulating layer which suppresses increase in leak current.

Abstract: An avalanche photodiode includes at least one crystal layer having a larger band-gap than that of an absorption layer formed by a composition or material different from that of the absorption layer formed on a junction interface between a compound semiconductor absorbing an optical signal and an Si multiplication layer, and the crystal layer may be intentionally doped with n or p type impurities to cancel electrical influences of the impurities containing oxides present on the junction interface of compound semiconductor and surface of Si.

Abstract: An object of the present invention is to provide a nitride semiconductor based light-emitting device, which is low in operating voltage reduction and is high in performance, and a manufacturing method thereof. A first metal film is formed on a P-type conductive nitride semiconductor formed on a substrate, and then, a film (WOx) made of tungsten oxide is formed in superimposition, followed by annealing.

Abstract: The present invention provides a Be-based group II-VI semiconductor laser using an InP substrate and having a stacked structure capable of continuous oscillation at a room temperature. A basic structure of a semiconductor laser is constituted by using a Be-containing lattice-matched II-VI semiconductor above an InP substrate. An active laser, an optical guide layer, and a cladding layer are constituted in a double hetero structure having a type I band line-up in order to enhance the injection efficiency of carriers to the active layer. Also, the active layer, the optical guide layer, and the cladding layer, which are capable of enhancing the optical confinement to the active layer, are constituted, and the cladding layer is constituted with bulk crystals.

Abstract: An object of the present invention is to provide a nitride semiconductor based light-emitting device, which is low in operating voltage reduction and is high in performance, and a manufacturing method thereof. A first metal film is formed on a P-type conductive nitride semiconductor formed on a substrate, and then, a film (WOX) made of tungsten oxide is formed in superimposition, followed by annealing.

Abstract: A super-lattice structure is used for a portion of a laser device of a self-aligned structure to lower the resistance of the device by utilizing the extension of electric current in the layer, paying attention to the fact that the lateral conduction of high density doping in the super-lattice structure is effective for decreasing the resistance of the laser, in order to lower the operation voltage and increase the power in nitride type wide gap semiconductor devices in which crystals with high carrier density are difficult to obtain and the device resistance is high.

Abstract: In the semiconductor laser or electro-absorption optical modulator that includes strained quantum well layers as active layers, making laser characteristics or modulator characteristics adequate has seen the respective limits since band structures, especially, ?Ec and ?Ev, have been unable to be adjusted independently. This invention is constructed by stacking an n-type InGaAlAs-GRIN-SCH layer 3, an MQW layer 4, a p-type InGaAlAs-GRIN-SCH layer 5, a p-type InAlAs electron-stopping layer 6, and others, in that order, on an n-type InP wafer 1; wherein the MQW layer 4 includes InGaAlAs-strained quantum well layers and InGaAlAsSb-formed barrier layers each having strain of an opposite sign to the strain applied to the quantum well layers.

Abstract: In the semiconductor laser or electro-absorption optical modulator that includes strained quantum well layers as active layers, making laser characteristics or modulator characteristics adequate has seen the respective limits since band structures, especially, ?Ec and ?Ev, have been unable to be adjusted independently. This invention is constructed by stacking an n-type InGaAlAs-GRIN-SCH layer 3, an MQW layer 4, a p-type InGaAlAs-GRIN-SCH layer 5, a p-type InAlAs electron-stopping layer 6, and others, in that order, on an n-type InP wafer 1; wherein the MQW layer 4 includes InGaAlAs-strained quantum well layers and InGaAlAsSb-formed barrier layers each having strain of an opposite sign to the strain applied to the quantum well layers.

Abstract: The most important task in realizing a downsized and low cost THz band spectroscopic and fluoroscopic instrument is to achieve downsizing and cost reduction of oscillators used in the instrument. A metal base transistor is used for an active element of the oscillator. In order to improve the maximum oscillation frequency of the transistor to several THZ, InN having a high electron saturation velocity or a material mainly composed of InN is used for a collector layer. In order to obtain characteristics with excellent reproducibility, it is useful to insert InGaN into an interface between the collector layer and the base layer. Using the metal base transistor of the present invention makes it possible to constitute an oscillator allowing a THz band oscillation. Further, the present invention provides a spectroscopic instrument applying this oscillator to at least one of a signal source and a local oscillator.

Abstract: An avalanche photodiode includes at least one crystal layer having a larger band-gap than that of an absorption layer formed by a composition or material different from that of the absorption layer formed on a junction interface between a compound semiconductor absorbing an optical signal and an Si multiplication layer, and the crystal layer may be intentionally doped with n or p type impurities to cancel electrical influences of the impurities containing oxides present on the junction interface of compound semiconductor and surface of Si.

Abstract: A method and equipment for detecting an explosive, etc. are disclosed. A specified portion highly likely to contain an explosive, etc. is extracted based on the X-ray image obtained by radiating an X ray on an object to be inspected. An electromagnetic wave containing the terahertz wave is radiated on the specified portion thus extracted. The presence or absence of the explosive, etc. is determined based on at least one of the absorption spectrum and the reflection spectrum of the electromagnetic wave at the specified portion.

Abstract: An avalanche photodiode includes at least one crystal layer having a larger band-gap than that of an absorption layer formed by a composition or material different from that of the absorption layer formed on a junction interface between a compound semiconductor absorbing an optical signal and an Si multiplication layer, and the crystal layer may be intentionally doped with n or p type impurities to cancel electrical influences of the impurities containing oxides present on the junction interface of compound semiconductor and surface of Si.

Abstract: Reducing a dark current in a semiconductor photodetector provided with a second mesa including an regrown layer around a first mesa. An n-type buffer layer, a n-type multiplication layer, a p-type field control layer, a p-type absorption layer, a cap layer made of p-type InAlAs crystal, and a p-type contact layer 107 are made to grow on a main surface of a n-type substrate. Thereafter the p-type contact layer, the p-type cap layer, the p-type absorption layer and the p-type field control layer are patterned to form a first mesa. Next, after making a p-type regrown layer selectively grow around the first mesa or by forming a groove in the regrow layer located in a vicinity of the p-type cap type during a step of the selective growth, the p-type cap layer containing Al and the regrow layer are separated owing to the groove such that no current path is formed between both layers.

Abstract: An ultrahigh speed, high sensitivity photodetector, optical module and/or optical transmission device made by reducing the size of a surface illuminated type photodetector to decrease capacitance C. The effective detecting area on a side of the substrate that is opposite to a light incidence side of the substrate in a surface illuminated type photodetector and that is reached by the incident light passing through the semiconductor includes a plurality of ohmic contact areas and a reflector. The reflector may be a laminate comprised of two films in contact with the semiconductor including a transparent film (lower) and a metal film (upper). The size of the ohmic contacts may be small when compared to the wavelength of light incident on the surface of the photodetector. The photodetector may be used in ultrahigh speed, high sensitivity optical modules, semiconductor photo receivers and optical transmission devices with increased transmission capacities.