| 摘要 |
PURPOSE:To prevent mirror breakdown and thus contrive to stabilize the characteristic and improve the reliability by forming a window layer in accordance with the structure of a quantum well. CONSTITUTION:Under mentioned each layer 12-15 is successively formed on an N type GaAs substrate 11. An N type GaAs buffer layer 12 has the impurity concentration equal to that of the substrate 11, and an N type AlxGa1-xAs clad layer 13 has a forbidden band width larger than that of a well layer 14. The structure of a quantum well 14 is formed by alternately laminating e.g. well layers and barrier layers both in non-doping by means of GaAs for the well layer and AlxGa1-xAs for the barrier layer. By the way, the thickness of the well layer should be a de Broglie's wave length. A P type AlxGa1-xAs clad layer 15 is the same as the layer 13. In this constitution, the light generated in the well layer is confined in the layers 13 and 15 and then go toward a resonance mirror plane M caused by cleavage. The mirror plane M has the forbidden band width increased more than in the well layer, thus obtaining the effect of a window region. |
