Abstract: A compound semiconductor device based on gallium nitride which can have a thick gallium nitride semiconductor layer serving to prevent cracks or defects attributable to a strain caused by a difference in lattice constant or coefficient of thermal expansion. Between a contact layer 4 consisting of a film of n-type GaN and a clad layer 5 consisting of a film of a n-type AlyGa1−yN is interposed a crack-preventive buffer layer 5 having both of the compositions of the two films.

Abstract: In the manufacture of a semiconductor laser device, a low temperature buffer layer is grown on a sapphire substrate at a growth rate of 25 to 30 Å/sec. On the low temperature buffer layer, an n-GaN layer, a anti-crack layer, an n-cladding layer, an n-guide layer, an MQW active layer, a p-carrier blocking layer, a p-guide layer, a p-cladding layer and a p-contact layer are grown in this order. The growth of the low temperature buffer layer at the high growth rate allows a good low temperature buffer layer to be stably provided with good reproducibility. Thus, good crystallinity and electrical characteristics can stably be provided in the above layers.

Abstract: A method of preparing a nitride semiconductor capable of forming a nitride-based semiconductor layer having a small number of dislocations as well as a small number of crystal defects resulting from desorption with excellent crystallinity on the upper surface of a substrate through a small number of growth steps is proposed. The method of preparing a nitride-based semiconductor comprises steps of forming a mask layer on the upper surface of a substrate to partially expose the upper surface of the substrate, forming a buffer layer on the exposed part of the upper surface of the substrate and the upper surface of the mask layer and thereafter growing a nitride-based semiconductor layer. Thus, the outermost growth surface of the nitride-based semiconductor layer laterally grown on the mask layer does not come into contact with the mask layer.

Abstract: A GaN layer is grown on a sapphire substrate, an SiO2 film is formed on the GaN layer, and a GaN semiconductor layer including an MQW active layer is then grown on the GaN layer and the SiO2 film using epitaxial lateral overgrowth. The GaN based semiconductor layer is removed by etching except in a region on the SiO2 film, and a p electrode is then formed on the top surface of the GaN based semiconductor layer on the SiO2 film, to join the p electrode on the GaN based semiconductor layer to an ohmic electrode on a GaAs substrate. An n electrode is formed on the top surface of the GaN based semiconductor layer.

Abstract: A semiconductor laser device is constructed by stacking a buffer layer, an undoped GaN layer, an n-GaN contact layer, an n-InGaN crack preventing layer, an n-AlGaN cladding layer, a light emitting layer, a p-AlGaN cladding layer, and a p-GaN contact layer in this order. A ridge portion comprising the p-GaN contact layer and the p-AlGaN cladding layer is formed, and the thickness of the p-AlGaN cladding layer in the ridge portion is less than 0.3 &mgr;m.

Abstract: A GaN layer is grown on a sapphire substrate, an SiO2 film is formed on the GaN layer, and a GaN semiconductor layer including an MQW active layer is then grown on the GaN layer and the SiO2 film using epitaxial lateral overgrowth. The GaN based semiconductor layer is removed by etching except in a region on the SiO2 film, and a p electrode is then formed on the top surface of the GaN based semiconductor layer on the SiO2 film, to join the p electrode on the GaN based semiconductor layer to an ohmic electrode on a GaAs substrate. An n electrode is formed on the top surface of the GaN based semiconductor layer.

Abstract: In the manufacture of a semiconductor laser device, sequentially grown on a sapphire substrate in the following order are a buffer layer, a first undoped GaN layer, a first super lattice defect reducing layer, a second undoped GaN layer, a second super lattice defect reducing layer, a third undoped GaN layer, a third super lattice defect reducing layer and a fourth undoped GaN layer. A device structure is then formed thereon. The first to third super lattice defect reducing layers each include five pairs of InGaN and AlGaN films alternately placed on one another in this order.

Abstract: A method of manufacturing a light emitting device, including the steps of: forming an active layer composed of a compound semiconductor containing indium by a vapor phase growth method; and forming a cap layer composed of a compound semiconductor on said active layer by a vapor phase growth method at a growth temperature approximately equal to or lower than a growth temperature for said active layer.

Abstract: A light emitting device includes a cladding layer composed of a III-V group nitride system semiconductor of a first conductivity type, an active layer formed on the cladding layer of the first conductivity type and composed of a III-V group nitride system semiconductor containing In, an undoped cap layer formed on the active layer and composed of a III-V group nitride system semiconductor, and a cladding layer formed on the cap layer and composed of a III-V group nitride system semiconductor of a second conductivity type.

Abstract: A lid for a container, which is easy for separated disposal. The lid has a main body portion (1a) and a projected portion (1b) integrally formed at the substantially central portion of the upper surface (1a1) of the main body portion (1a), whereby the lid (1) for the container covers an opening portion of a bottle (container) (2) and a seal plug for blocking this opening portion.

Abstract: A method and apparatus for controlling a travelling body having a main body and a steering device along a predetermined route includes a plate-shaped indicator disposed perpendicular to an axis of the main body, an optical pointer emitting light of a first color showing the steering direction of the steering device, a laser beam illuminating the indicator with a laser beam spot of a second color, a TV camera monitoring the optical pointer and the laser beam spot on the indicator, a color separator separating image information of the optical pointer and the laser beam spot, an image processing unit computing position data of the optical pointer and the laser beam spot for outputting steering direction information and optical pointer position information, a fuzzy operation unit processing a steering command using the optical pointer position information, and comparator computing a controlling command for operating the steering device by calculating the difference between the steering command and the steering di

Abstract: A process for producing a metal phthalocyanine pigment which comprises the steps of: reacting phthalic anhydride or a derivative thereof with urea or a derivative thereof with heating in the presence of a catalyst either in the presence or absence of an organic solvent; adding to the reaction mixture of the preceding step a metal or its compound capable of constituting the core of the metal phthalocyanine either alone or together with urea or a derivative thereof, without isolating the reaction product from the reaction mixture of the preceding step; and allowing the reaction mixture to react while simultaneously applying a mechanical grinding force in the presence or absence of a grinding agent.

Abstract: A cap of a bottle for a medical fluid having a seal stopper at an opening. The cap has a projection integrally extending from a cap body of a cap member. Around the base portion of the projection, there is formed a thin-plate portion for bending and removing the projection from the cap body with ease and safety. The thin plate comprises a continuously recessed groove.

Abstract: A high voltage converter apparatus having overvoltage protection circuits for thyristors is disclosed in which, in order to protect series-connected thyristors in the converter against overvoltage, the converter is stopped when the overvoltage is generated by a trouble in the primary circuit of a pulse transformer, which is included in a gate circuit for the thyristors, and one of the overvoltage protection circuits, each of which is connected between an anode and a gate of a corresponding thyristor, is prevented from being operated when the overvoltage is generated by a trouble in the secondary circuit of the pulse transformer.