| 摘要 |
The present invention discloses a semiconductor barrier photo-detector having a structure of the form nBn, comprising: an n-type photon absorbing layer (102) of a first energy bandgap; a middle barrier layer (104), an intermediate layer (106) being a semiconductor structure; and a contact layer (108) of a third energy bandgap, wherein the layer materials are selected such that the first energy bandgap of the photon absorbing layer (102) is narrower than that of said middle barrier layer (104); wherein the material composition and thickness of said intermediate layer (106) are selected such that the valence band of the intermediate layer lies above the valence band in the barrier layer (104) to create an efficient trapping and transfer of minority carriers from the barrier layer (104) to the contact layer (108) such that a tunnel current through the barrier layer (104) from the contact layer (108) to the photon absorbing layer (102) is less than a dark current in the photo-detector and the dark current from the photon-absorbing layer (102) to said middle barrier layer (104) is essentially diffusion limited and is due to the unimpeded flow of minority carriers, thus reducing generation-recombination (GR) noise of the photo-detector. The principles of the present invention also apply to inverted polarity structures of the form pBp in which all the doping polarities and band alignments described above are reversed. |
