Patent ID: 8546758

Claim:
A food quality examination device configured to inspect the quality of food comprising a light receiving element composed of III-V group semiconductor or an array of the light receiving elements, the light receiving element being configured to receive near-infrared light, wherein the light receiving element includes an absorption layer with a multiquantum well structure formed on an InP substrate, the absorption layer has a bandgap wavelength of 1.8 μm to 3 μm, a diffusion concentration distribution control layer composed of III-V group semiconductor and having a first surface and a second surface on opposite sides of the diffusion concentration distribution control layer, wherein the first surface is in contact with the absorption layer on a side of the absorption layer opposite the side adjacent to the InP substrate, the bandgap energy of the diffusion concentration distribution control layer is lower than that of the InP substrate, the concentration of impurity element selectively diffused in the diffusion concentration distribution control layer decreases in a direction from the second surface toward the first surface such that the concentration of the impurity element is 5×10 16 /cm 3 or less at an interface between the diffusion concentration distribution control layer and the absorption layer; and the light receiving element receives light coming through or reflected from the food, the light having at least one wavelength of 3 μm or less, thereby performing the inspection.