In1yGaxAs

In1−xGaxAs, commonly written as In1−xGaxAs, is a ternary III–V semiconductor alloy formed from indium arsenide (InAs) and gallium arsenide (GaAs). The composition parameter x, varying from 0 to 1, allows continuous tuning of the material’s lattice constant, bandgap, and optical properties. The name In1yGaxAs appears in some sources, but the standard notation describes the indium content as 1−x and the gallium content as x.

The crystal lattice of In1−xGaxAs follows Vegard’s law, with the lattice constant approximated by a ≈ (1−x)a(InAs) + x a(GaAs). This enables lattice tuning between the GaAs and InAs extremes. Compositions chosen for growth on GaAs or InP substrates determine the degree of strain; some lattice-matched compositions exist with respect to InP, while higher indium content on GaAs typically introduces tensile strain and dislocations if not properly managed with buffers.

Electronic and optical properties are dominated by a direct bandgap across the full composition range, described by Eg(x) ≈ (1−x)Eg(InAs) + xEg(GaAs) − b x(1−x), where b is a bowing parameter (typically around 0.3–0.5 eV in literature). Eg spans roughly from the indium-rich to gallium-rich ends, allowing emission and absorption in the infrared to near-infrared. Electron mobilities in InGaAs can be high, making the alloy suitable for high-speed devices.

Growth and fabrication are typically accomplished by molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD/MOVPE). Layered structures often employ buffer layers to reduce defects and to enable precise composition control, enabling integration with GaAs- or InP-based optoelectronic systems.

Applications include infrared optoelectronics, high-speed electronics, and heterostructures for photodetectors and laser components on common semiconductor platforms.