Patent ID: 8373156

Claim:
A biological component detection device for detecting a component of a biological object using light in the near-infrared region, comprising a light-receiving element composed of III-V group semiconductor, that receives light in the near-infrared region, wherein, the light-receiving element including an absorption layer formed on an InP substrate and having a multiple quantum well structure, the absorption layer having a bandgap wavelength of 1.8 μm or more and 3 μm or less, a diffusion concentration distribution control layer made of III-V group semiconductor is disposed in contact with the absorption layer on a surface side of the absorption layer, the surface side being opposite to the InP substrate, the diffusion concentration distribution control layer having a bandgap smaller than that of InP, wherein, in the light-receiving element, a pn-junction is formed by selectively diffusing an impurity element through the diffusion concentration distribution control layer so as to reach the absorption layer, the concentration of the impurity element in the absorption layer is 5×10 16 /cm 3 or less, the diffusion concentration distribution control layer has an n-type impurity concentration of 2×10 15 /cm 3 or less before the diffusion, the diffusion concentration distribution control layer having a portion adjacent to the absorption layer, the portion having a low impurity concentration, and the detection is performed by receiving, with the light-receiving element, light having at least one wavelength of 3 μm or less, the light constituting light transmitted through or reflected from the biological object.