AlAs, or aluminum arsenide, is a III-V semiconductor compound that forms in a zincblende crystal structure. It is often used in conjunction with other III-V semiconductors like GaAs (gallium arsenide) to form heterostructures and quantum wells, which are essential components in modern optoelectronic devices. AlAs has a direct bandgap of approximately 2.16 eV at room temperature, making it transparent to visible light but absorbent in the ultraviolet range. One of its key attributes is its nearly lattice-matched compatibility with GaAs, allowing for high-quality epitaxial growth of multilayer structures. Such layered systems are critical in applications like high-electron-mobility transistors (HEMTs), quantum cascade lasers, and photodetectors. AlAs is also notable for its high thermal conductivity and good electron mobility, which makes it valuable in electronic applications that require effective heat dissipation. However, due to its composition including arsenic, AlAs must be handled with appropriate safety measures. Overall, AlAs remains a material of substantial scientific and technological interest, particularly for its role in enabling high-performance optoelectronic devices.