| 摘要 |
PURPOSE:To implement a direct transition type band structure, whose effective state density is high, and to obtain a semiconductor laser having high light emitting efficiency, by using a quantum well structure for an active layer, and using a mixed crystal semiconductor, which has a composition in the vicinity of the changing point between direct transition and indirect transition, for the material of the quantum well layer. CONSTITUTION:A semiconductor laser comprises a first conducting type, e.g., P-type AlGaAs clad layer 14, an AlGaAs quantum well active layer 15 and a second conducting type, e.g., N-type AlGaAs clad layer 16. The active layer 15 has a quantum well structure, in which AlyGa1-yAs barrier layers and AlzGa1-zAs well layers are repeatedly laminated. The composition of the AlzGa1-zAs is located in the vicinity of the changing point between a direct transition type and an indirect transition type. Therefore, the value of (z) is approx. 0.35-0.45. The composition of (y) of the barrier layer is set at, e.g., about 0.5-0.55. The composition of the clad layer is set at, e.g., about 0.7. In this structure, when, e.g., the composition is set at approx. z=0.4, the wavelength of oscillation is 600nm. Thus a semiconductor laser in the 600nm band can be obtained. |
