SEMICONDUCTOR HETEROSTRUCTURE

A strained semiconductor heterostructure (10) comprises an injection region comprising a first emitter layer (11) and a second emitter layer (12) and a light generation layer (13) positioned between the emitter layers (11, 12). An electron capture region (14) is positioned between the light generation layer (13) and the second emitter layer (12), said electron capture region comprising a capture layer (16) adjacent to the second emitter layer, and a confining layer (15) adjacent to said electron capture layer. According to the present invention, the concentration of electrons in the second emitter layer (12) is adjusted to equal to the product of concentration of holes in the first emitter layer (11), the ratio of the diffusion coefficient for holes in the second emitter layer (12) and the diffusion coefficient for electrons in the first emitter layer (11), and the ratio of the diffusion length for electrons in the first emitter layer (11) and the diffusion length for holes in the second emitter layer (12).