PURPOSE: To obtain the oscillation (light-emission) wavelength ranging from the visible region to that of inflared rays by a method wherein, a ZnSe single crystal substrate and a III-V group semiconductor are latice-matched with the substrate is epitaxially grown.

CONSTITUTION: Pertaining to the semiconductor light source, wherein ZnSe crystal of compound semiconductor is used as a substrate and a III-V compound semiconductor is used as an active layer, In1-xGaxAsyP1-y is concretely taken into consideration as a III-V group compound semiconductor. The first diagram shows that the composition ratio (x) of Ga and the composition ratio (y) of As are considered as the coordinate of the bottom face in In1-xGaxAsyP1-y, and the grating constant of the crystal having said composition is considered to be ordinate. The grating constant of ZnSe is 5.6687, and the relation between (y) and (x) which are the composition lattice-matching with the above grating constant is y=2.08x-1. The heavy line in the diagram shows the locus of the (x) and (y) which satisfies (to latice matches, in other words) the above relation.