| 摘要 |
PROBLEM TO BE SOLVED: To form an infrared LED in which high speed high output of DDH structure having an n-type layer formed on an n-type GaAs substrate does not cause failure of a thyristor by limiting the maximal carbon concentration to a specified value or below at a predetermined distance from the interface of a second n-type layer to a first n-type layer. SOLUTION: From the results shown in Fig.6, it can be seen that when the compositional ratio of Al between an n-type clad layer and the clad layer at the interface of an active layer is larger than 0.25, absolute value of LED output is smaller than that when the compositional ratio of Al is 0.25 and the output decreases as the active layer is made thin. When the compositional ratio of Al is lower than 0.12, the output increases by making thin the active layer but the absolute value decreases. Consequently, an epitaxial substrate for fabricating an infrared LED in which high speed high output of DDH structure having an n-type layer formed on an n-type GaAs substrate does not cause failure of a thyristor can be obtained and an infrared LED can be fabricated on such an epitaxial substrate. |
