Abstract: A quantum wire structure includes a first layer having a thickness sufficiently smaller than a de Broglie wavelength of an electron wave in a medium, a second layer and a third layer which are disposed on and under the first layer and respectively have a forbidden band width larger than that of the first layer, wherein the first layer has a region with a relatively small curvature and a region with a relatively large curvature in its cross-section, and a width of the region with a relatively small curvature is 50 nm or less.

Abstract: A semiconductor microstructure is formed by forming a groove having a surface of a side wall and a surface of a bottom, and depositing a semiconductor layer in the groove so that a width of the semiconductor layer is defined by the surface of the side wall.

Abstract: A quantum wire laser comprises a first multi-layer structure which is formed on a substrate and includes at least one first quantum well layer sandwiched by barrier layers, a second multi-layer structure which is formed on a laminated cross-section of the first multi-layer structure and is obtained by successively laminating a first barrier layer having a band gap larger than that of the first quantum well layer, a second quantum well layer having a band gap nearly equal to that of the first quantum well layer, and a second barrier layer having a band gap larger than those of the first and second quantum well layers, wherein a region for confining electrons is disposed in at least one of regions in the vicinity of the first quantum well layer and the second quantum well layer.