aInAs

aInAs is a designation that may refer to two different semiconductor materials, depending on context, and is not a standardized single compound. It can denote amorphous indium arsenide (a-InAs) or the ternary alloy aluminum-indium-arsenide (AlInAs). The ambiguity means sources should specify which material is meant.

Amorphous indium arsenide (a-InAs) describes a non-crystalline form of indium arsenide. It is typically produced by deposition methods such as sputtering or chemical vapor deposition. Lack of long-range order leads to electronic and optical properties dominated by localized states, often resulting in higher resistivity and lower carrier mobility compared with crystalline InAs. The band gap in amorphous InAs is not fixed and depends on deposition conditions and the degree of disorder. Upon annealing, a-InAs can crystallize toward crystalline InAs. Potential applications are experimental and include thin-film electronic and optoelectronic layers where an amorphous III-V semiconductor is advantageous.

AlInAs denotes a ternary III-V alloy with the formula AlxIn1−xAs, where the aluminum content x tunes both the lattice constant and the bandgap. It crystallizes in the zinc blende structure when grown under appropriate conditions and is commonly grown by molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD). The lattice constant and bandgap follow Vegard-like behavior, ranging from InAs-like values (small x) to AlAs-like values (large x). This tunability enables lattice-matched barriers and cladding layers for GaAs- or InP-based heterostructures, as well as infrared optoelectronic and high-speed electronic devices.

See also: InAs, AlAs, GaAs, Vegard’s law, III–V semiconductors.