GaAs(Zn) electroluminescent diodes using a GaAs-Ga
xAl
1-xAs heterostructure design with external quantum efficiencies (300°K) of 10%, that 40 milliwatts of continuous output at a current of 1 ampere, have been developed. The heterostructure consists of a Ga
xAl
1-xAs(Zn) p-layer grown by liquid-phase epitaxy on an n-type GaAs(Si) substrate (

/cm
3) with the simultaneous diffusion of Zn a distance of ∼ 2 µm into the substrate.