| 摘要 |
PURPOSE:To improve the coupling efficiency for LED and fiber by providing a current concentrating mechanisms at the upper and lower sides of a light-emitting layer, in a light-emitting diode suitably used in optical fiber communication. CONSTITUTION:The LED consists of metal electrode layer 1, n-type GaAs substrate 2, n-type GaAlAs layer 3, p-type GaAs layer 4, p-type GaAlAs layer 5, n-type GaAlAs layer 6, p-type GaAlAs layer 7, and metal electrode layer 9 having opening 8. P-type GaAs layer 10 is buried between n-type GaAs substrate 2 and n-type GaAlAs layer 3, excluding the part immediately below opening 8. When voltage is impressed on a LED of this structure, reverse biasing takes place not only between layer 5 and layer 6 but also between layer 10 and layer 2. As a result, with its path choked in circular form, current flows into layer 5. When it passes through layer 4, it slightly expands, but it is choked again and flows into substrate 2. Consequently, most of the current flowing to the LED chip concentrates immediately below opening 8 flowing toward substrate 2, so that the coupling efficiency is improved. |
