Patent ID: 7795640
Filing Date: 2010-09-14
Classification: H01L

Abstract:
1. A photo-detector comprising a heterostructure comprising a first heterojunction, formed by an n-type photon absorbing material layer of a certain energy bandgap and an n-type middle barrier layer, and a second heterojunction, formed by said n-type middle barrier layer and a p-type contact layer, the layer materials being selected such that the energy bandgap of the photon absorbing layer is narrower than that of said middle barrier layer, the first and second heterojunctions being thus configured and operable to prevent creation of a depletion region in said photon absorbing layer when a bias voltage is applied across the heterostructure such that a tunnel current of electrons from the contact layer to the photon absorbing layer is less than a dark current in the photo-detector and the dark current from the photon-absorbing layer to the barrier layer is essentially diffusion limited, thus reducing generation recombination (GR) noise of the photo-detector.