| 摘要 |
PURPOSE:To obtain a photodetector having high sensitivity by sequentially disposing semiconductor active layers for generating a light and detecting the light on a semiconductor substrate in a thicknesswise direction and controlling the forbidden band width of the active layer to reduce the decrease in the performance of the inside active layer. CONSTITUTION:Semiconductor active layers for generating a light and for detecting the light are sequentially disposed on a semiconductor substrate in the thicknesswise direction and the deterioration in the performance of the inside active layer can be reduced by controlling the forbidden band width of the active layer. That is, the second photodetecting active layer 5 having wider forbidden band width than the first active layer 3 formed on the first layer 2 is formed on the substrate 1. In this manner it can eliminate problems of the production of spike voltage and the occurrence of nonoperating time upon switching of the bias with high sensitivity of the photodetector. |
