GaAs1xPx

GaAs1-xPx, also written GaAs1−xPx, is a ternary III–V semiconductor alloy formed by substituting phosphorus for arsenic in gallium arsenide. The composition parameter x ranges from 0 to 1, yielding GaAs (x=0) to GaP (x=1). The alloy crystallizes in the zinc blende structure and inherits many properties from the parent compounds.

The introduction of phosphorus to GaAs widens the electronic bandgap; as x increases, the bandgap energy increases and the emission wavelength shifts from the near-infrared toward the visible. This tunability allows devices to cover a broad range of wavelengths. The lattice constant decreases with increasing phosphorus content, leading to lattice mismatch when grown on GaAs substrates, which affects strain, defects, and device performance.

GaAs1-xPx is typically grown by epitaxial methods such as metal-organic chemical vapor deposition (MOCVD, also called MOVPE) or molecular beam epitaxy (MBE) on GaAs or related substrates. Growth conditions, including temperature, group-III and phosphorus flux, and strain management, must be optimized to control composition, uniformity, and defect density.

Applications include optoelectronic devices such as light-emitting diodes and laser diodes spanning the visible to near-infrared, photodetectors, and heterostructures for high-speed electronics. It is also used in photovoltaic structures and as a component in broader GaAsP-based material systems.