| 摘要 |
PROBLEM TO BE SOLVED: To provide a photodiode that enables a THz operation with a stable output.SOLUTION: A photodiode has a pin type semiconductor structure comprising: a semiconductor layer structure formed by sequentially laminating an n-type contact layer 11, a low-concentration layer, and a p-type contact layer 16; and an n-electrode 18 and a p-electrode 17 respectively connected with the contact layers. The low-concentration layer is put into depletion at an operation. The low-concentration layer is adjacent to the n-type contact layer, and formed by laminating an electron drift layer 12, a light absorption layer 13, and a hole drift layer 14. Preferably, the photodiode is adjusted to required optical response characteristics by changing a thickness of the electron drift layer and a thickness of the hole drift layer, and the electric field intensity of at least one of the electron drift layer and the hole drift layer is set to be lower than that of the light absorption layer. The electron drift layer is n-type doped, and the hole drift layer is p-type doped. |
