Light receiving element, semiconductor epitaxial wafer, method for manufacturing the light receiving element, method for manufacturing the semiconductor epitaxial wafer, and detecting device

A light receiving element formed by using a group III-V compound semiconductor, the light receiving element comprising:

• an InP substrate that is transparent to light having a wavelength of 3 to 12 μm;
• a buffer layer having a thickness of 2 μm or more and located in contact with the InP substrate;
• and
• a light-receiving layer having a multiple quantum well structure and located in contact with the buffer layer,
• wherein the light-receiving layer has a cutoff wavelength of 3 μm or more and is lattice-matched with the buffer layer,
• the buffer layer is epitaxially grown on the InP substrate while a value |a2−a1|/a1 exceeds a range of a normal lattice-matching condition, where a2 represents a lattice parameter of the buffer layer and a1 represents a lattice parameter of the InP substrate,
• the buffer layer is constituted by a GaSb layer doped with Te, and the buffer layer has a carrier concentration of 1E18 cm−3 or more, and
• the light receiving element has a structure in which light is incident from a rear surface of the InP substrate.