Independently variable band gaps and lattice constants in GaAsP strained-layer superlattices

The capability of independently varying band gaps and lattice constants in ternary strained-layer superlattices has been experimentally demonstrated for the first time. High-quality GaAsxP1−x/GaP superlattices (0<x≤0.62, lattice mismatches up to 2.3%) were grown by metalorganic chemical vapor deposition and their band gaps and lattice constants were measured. The band gaps at each composition agree with calculated values, and differ significantly from the band gaps of bulk alloys with the same lattice constant. This newly demonstrated capability could allow high-quality heterojunction devices to be grown in a variety of lattice-mismatched ternary systems.