Abstract: A semiconductor light emitting element includes a p-type electrode which in turn includes a contact electrode layer including at least a Pt layer. Particularly, the semiconductor light emitting element further includes a layered structure including at least an n-type cladding layer, an active layer, and a p-type cladding layer; and a p-type contact layer formed above the layered structure, and the contact electrode layer is formed on the p-type contact layer.

Abstract: A distributed feedback semiconductor laser which includes a semiconductor substrate of a first conductive type; a semiconductor multi-layer structure provided on the semiconductor substrate and including an active layer for generating laser light; and a gain-coupled diffraction grating provided between the semiconductor substrate and the semiconductor multi-layer structure. The diffraction grating includes a plurality of curved projections periodically arranged at a surface of the semiconductor substrate and a quantum well light absorption layer for covering the plurality of curved projections. The quantum well light absorption layer includes a light absorption area having a first thickness at each border between two adjacent curved projections and a non-light absorption area having a second thickness which is smaller than the first thickness at a top of each of the curved projections.

Abstract: The semiconductor laser device of the invention includes: a strained quantum well structure including a well layer and a barrier layer, and a semiconductor substrate for supporting the strained quantum well structure. In the semiconductor laser device, at least one of the well layer and the barrier layer is composed of a mixed crystal where an atomic ordering is generated.

Abstract: A multi quantum well semiconductor laser includes an InP substrate and a multi-layered structure formed on the InP substrate, lasing at 1.29 .mu.m to 1.33 .mu.m wavelength, wherein the multi-layered structure includes at least a multi quantum well active layer, the multi quantum well active layer including InGaAsP well layers and InGaAsP barrier layers alternately provided, the InGaAsP barrier layers are lattice matched with the InP substrate, and a bandgap wavelength of the InGaAsP barrier layers is substantially equal to 1.05 .mu.m.

Abstract: The semiconductor laser of the invention includes: a semiconductor substrate of a first conductivity type; a stripe-shaped multilayer structure, formed on the semiconductor substrate, the stripe-shaped multilayer structure including an active layer; and a current blocking portion formed on the semiconductor substrate on both sides of the stripe-shaped multilayer structure, wherein the current blocking portion has a first current blocking layer of a second conductivity type, and a second current blocking layer of the first conductivity type formed on the first current blocking layer, the first current blocking layer includes a low-concentration region having a relatively low concentration of an impurity of the second conductivity type, and a high-concentration region having an impurity concentration which is higher than that of the low-concentration region, and the low-concentration region is provided at a position closer to the stripe-shaped multilayer structure than the high-concentration region.

Abstract: A distributed feedback semiconductor laser which includes a semiconductor substrate of a first conductive type; a semiconductor multi-layer structure provided on the semiconductor substrate and including an active layer for generating laser light; and a gain-coupled diffraction grating provided between the semiconductor substrate and the semiconductor multi-layer structure. The diffraction grating includes a plurality of curved projections periodically arranged at a surface of the semiconductor substrate and a quantum well light absorption layer for covering the plurality of curved projections. The quantum well light absorption layer includes a light absorption area having a first thickness at each border between two adjacent curved projections and a non-light absorption area having a second thickness which is smaller than the first thickness at a top of each of the curved projections.

Abstract: The semiconductor laser comprises a Sn doped InP substrate 1, n-InGaAsP wave guide layer 2, 5 nm thick InGaAs well layer 3, 3.5 nm thick undoped InGaAsP layer 4, 3 nm thick p-InGaAsP modulation doping layer 5, 3.5 nm thick undoped InGaAsP layer 6, a modulation doping quantum well layer 7 with ten wells, a 90 nm thick p-InGaAsP layer 8, a p-InP clad layer 9 (Zn=7.times.10.sup.17 cm.sup.-3), p-n-p current block layer 10, and a mesa-shaped active layer region 11. An Au/sn n-electrode 12 and if Au/Zn p-electrode 13 are formed by vapor deposition to complete the laser structure.

Abstract: An n-InP buffer layer 102, an InGaAsP active layer 103, a p-InP cladding layer 104 and a p-InGaAsP surface protective layer 105 are successively epitaxially grown on an n-InP substrate 101 having a (100) plane as a main plane. An etching mask 106, an insulating film, is formed in a stripe in the <011> direction by photolithography and dry etching. Using a solution comprising a mixture of hydrochloric acid, oxygenated water and acetic acid, the n-InP buffer layer 102 is etched to a depth lower than the p-InP cladding layer 103, to form a mesa stripe 107. Next, the insulating film 106 is removed and the p-InGaAsP surface protective layer 105 is removed using a solution comprising a mixture of sulfuric acid and oxygenated water. Thereafter, InP current blocking layers 108 and 109 are selectively formed at the regions other than the mesa stripe 107 by the liquid-phase epitaxial growth. Thus, a buried heterostructure semiconductor laser is fabricated, having good laser characteristics and a high reliability.

Abstract: A semiconductor device includes a semiconductor substrate having a plurality of mesa stripes whose widths are different from each other. Quantum well layers are formed on the mesa stripes respectively and have different band gap energies. The quantum well layers include ultra-thin epitaxial layers respectively. Semiconductor elements are formed on the mesa stripes respectively and include the quantum well layers respectively. Thicknesses of the ultra-thin layers are preferably equal to or less than 500 angstroms.