GaAsSb

GaAsSb is a III-V semiconductor alloy in which antimony partially substitutes arsenic in gallium arsenide, described by the formula GaAs1−x Sb x. By changing the Sb content x, the material's electronic and structural properties can be tuned, enabling bandgap engineering for devices operating from near-infrared to mid-infrared wavelengths. The alloy maintains the zinc blende crystal structure characteristic of GaAs.

Lattice constant increases with Sb, leading to strain in epitaxial layers. This enables lattice matching to substrates such as GaAs or GaSb for different Sb fractions, and is exploited to create strained quantum wells and high-mobility channels. The bandgap decreases with increasing Sb content, allowing emission and absorption at longer wavelengths.

Common growth methods are molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). Sb incorporation is sensitive to temperature and surface kinetics, which can complicate composition control and increase defect density if not carefully managed. Growth often uses buffer layers and strain management strategies to improve material quality.

Applications include infrared photodetectors and light-emitting devices, such as laser diodes and quantum well structures, as well as tunnel junctions and high-efficiency multijunction solar cells. GaAsSb is studied as a tunable layer in heterostructures integrated with GaAs and GaSb-based devices.