Indium gallium arsenide phosphide (GaxIn1−xAsyP1−y) is a quaternary compound semiconductor material, an alloy of gallium arsenide, gallium phosphide, indium arsenide, or indium phosphide. This compound has applications in photonic devices, due to the ability to tailor its band gap via changes in the alloy mole ratios, x and y. Indium phosphide-based photonic integrated circuits, or PICs, commonly use alloys of GaxIn1−xAsyP1−y to construct quantum wells, waveguides and other photonic structures, lattice matched to an InP substrate, enabling single-crystal epitaxial growth onto InP.