Semiconductor laminate, light-receiving element and method of manufacturing semiconductor laminate

Provided is a semiconductor laminate comprising: a first-conductivity-type layer made from a group III-V compound semiconductor, the conductivity type of which is a first conductivity type; a quantum-well light-receiving layer made from a group III-V compound semiconductor; and a second-conductivity-type layer made from a group III-V compound semiconductor, the conductivity type of which is a second conductivity type that is different from the first conductivity type. The first-conductivity-type layer, the quantum-well light-receiving layer and the second-conductive-type layer are laminated in that order. The thickness of the quantum-well light-receiving layer is 0.5 μm or more. The carrier concentration in the quantum-well light-receiving layer is 1×10 16 cm -3 or less.