| 摘要 |
PURPOSE:To enhance the light emitting efficiency by reducing the value of the composition of a buffer layer in a direction of a substrate side from a double hetero structure side. CONSTITUTION:The material of a buffer layer 2 is formed of AlzGa1-zAs, and the value of the composition (z) is set to reduce from a double hetero structure side in the direction of the side of a substrate 1. In this case, the value of the composition (z) is distributed to linearly reduce from a clad layer 4 to the substrate 1. This composition (z) is gradually varied from GaAs of z=0 of the substrate 1 to z=x of AlGa1-xAs of the layer 4. According to this type, the function of producing and returning the light advanced from an active layer to the substrate side effectively in the direction of a window, the conversion efficiency of externally producing the light can be enhanced. |
