A method produces a light-receiving device by growing a light-receiving layer having an undoped multi-quantum well structure; growing a cap layer on the light-receiving layer while the cap layer is doped with a p-type impurity during its growth; growing a mesa structure; growing a protective film on surfaces of the mesa structure; and annealing to form a p-n junction. The mesa structure is defined by a surrounding trench. Alternatively, a selective growth mask can be formed on the light-receiving layer whereafter the cap layer is grown on the light-receiving layer by use of the mask. In the alternative, the p-n junction is formed by diffusing p-type impurity from a p-type contact layer of the cap layer through a concentration adjusting layer thereof to the light-receiving layer.