| 摘要 |
PROBLEM TO BE SOLVED: To provide an epitaxial substrate for manufacturing a high-output/long service life GaAlAs infrared light-emitting diode of a DDH structure. SOLUTION: The dopant of a first p-type layer 2 is Zn, that of p-type clad layer 3 and p-type active layer 4 is Ge, and that of n-type clad layer 5 and second n-type layer 6 is Te. Here, the average carrier concentration of the n-type clad layer 5 and second n-type layer 6 is 8×1017-2×1018 cm-3, the thickness of n-type clad layer is 60 μm or larger, the sum of Zn concentration and Ge concentration in the second n-type layer is 1×1017 cm-3 or smaller, the dopant concentration in a region of the interface, between the n-type clad layer 5 and the second n-type clad layer 6, which is within 3 μm in the direction toward the second n-type layer side is 3×1017 cm-3 or higher, and Al composition of the n-type clad layer 5 and the second n-type layer 6 is set such that 0<y1<0.35 as well as 0<y2<0.35. |
