LIGHT RECEIVING ELEMENT AND MANUFACTURING METHOD FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a light receiving element that can enhance the photosensitivity at a long wavelength side of near infrared light without increasing dark current.SOLUTION: A light receiving element has a light receiving layer 3 which is located on an InP substrate 1 and has a multiquantum well structure of type 2 in which an InGaAs layer 3a and a GaAsSb layer 3b are alternately laminated. The composition gradient is set in the thickness direction so that the band gap energy of InGaAs or GaAsSb decreases toward the upper surface or lower surface in the InGaAs layer or the GaAsSb layer, and the band gap energy of a plane is set to be smaller than the band gap energy of the average composition. The type 2 transition on the plane is longer in wavelength than the type 2 transition in average composition.