Abstract: There is provided a strained quantum well layer semiconductor laser device that shows an improved temperature dependency of the threshold current and a high frequency performance while maintaining an excellent low threshold current operability. A strained quantum well layer type semiconductor laser device according to the invention comprises a light emitting active layer 14 of a multilayer structure including a quantum well layer 14a and a barrier layer 14c and a pair of light confining layers 13, 15, respectively laid on and under the active layer, the quantum well layer being made of InAs.sub.y P.sub.1-y (0<y.ltoreq.1), the barrier layer and/or the light confining layers being made of In.sub.1-x Ga.sub.x P (0<x.ltoreq.1). Such a device shows an improved temperature dependency of the threshold current and a high frequency performance, while maintaining an excellent low threshold current operability because of the structural features of its active layer.

Abstract: There is provided a semiconductor laser device that can be driven for a high-output power level without degradation in the quality of the device. It comprises a double heterostructure including an active layer (5, 25) and an electrode layer (9, 29) arranged on a semiconductor substrate (1, 21) having a current injection region extending through the electrode layer (9, 29) and the active layer (5, 25), a structural scheme being provided either in a region located above the active layer (5, 25) or in a region covering an resonator of the active layer (5, 25) in order to reduce the injection current level of the device. With such an arrangement, the energy output level of the semiconductor laser device is remarkably enhanced and its reliability is greatly improved, because it can be driven for a high-output power level without degradation in the quality of the device.

Abstract: A method of growing a single semiconductor crystal with a flat top. In order to grow a single flat top crystal, the InP crystal is pulled up after the temperature drop of the melt has almost stopped, at a point in time when a meniscus at the interface of solid-liquid can be seen over the whole circumference of the surface of the melt. This prevents a facet from appearing at the shoulder portion of the crystal, thus reducing the generation of twin crystals and drastically improves retension of single crystal formation.

Abstract: A strained quantum well type semiconductor laser device is disclosed to comprise a plurality of layers including a quantum well active layer formed on a semiconductor substrate characterized in that tensile strained quantum well layers and compression strained barrier layers are stacked alternately to form said quantum well active layer and the quantum well layers are made of either InGaAs or InGaAsP and InP, when the semiconductor substrate is made of InP, InGaP or GaAs, respectively.

Abstract: Disclosed is a method of growing a single crystal of a compound semiconductor, in which a compound semiconductor material is loaded in a vertical crucible and the compound semiconductor material is converted into a single crystal by utilizing a seed disposed in the center of the bottom portion of the vertical crucible.

Abstract: This invention provides a buried-type semiconductor laser device that operates stably and reliably at a high temperature for a prolonged period of time. A buried-type semiconductor laser device according to the invention comprises a semiconductor substrate 2, a first ridge mesa 8 formed on said substrate 2, said first ridge mesa 8 being covered on the top with at least an active layer 4 and provided at both lateral edges with current blocking layers 9, 10 of p-n reverse junction semiconductors arranged along the active layer for confining electric currents, and a second ridge mesa 11 formed by said first ridge mesa 8 and said current blocking layers 9, 10 and provided at both lateral edges with a semi-insulating layer 13.

Abstract: An apparatus for manufacturing a single crystal of compound semiconductor consisting of Ga and As comprises a crucible storing Ga and having a seed crystal arranged at a lower end portion thereof a gas material susceptor, arranged below the crucible, for storing As, the gas material susceptor and the crucible being arranged in a growth susceptor to be capable of communicating with each other, a main heater for heating and melting Ga in the crucible and for cooling the melt Ga from a lower portion thereof to grow a single crystal, a sub heater for heating and evaporating As in the gas material susceptor and allowing the evaporated As to react with the melt Ga in the said crucible, and a magnetic field applying coil for applying a vertical magnetic field in the melt Ga and As in the crucible so that a surface of the melt in the crucible which is grown to a single crystal is lower in temperature at a central portion thereof than a peripheral portion thereof in a radial direction and at the same time projects upw

Abstract: A method and an apparatus for growing a crystal of a compound semiconductor, in which a heater, used to heat a boat for growing the semiconductor crystal, is disposed around an ampule containing the boat, and a melt of the compound semiconductor, which is prepared in the boat, is freezed gradually at a predetermined temperature gradient including the freezing point of the melt, from a crystal growth starting end of the boat to a crystal growth terminating end thereof, whereby a single crystal or a polycrystal is grown. At the start of crystal growth, a crystalline nucleus is formed by periodically changing the temperature of the crystal growth starting end of the boat, in descending and ascending modes, within a temperature range lower than the melting point of the compound semiconductor, after once lowering the temperature of the starting end to a level lower than the melting point by means of a heater block opposed to the starting end.