AlGaAsGaAs

AlGaAsGaAs refers to aluminum gallium arsenide, a ternary III-V semiconductor alloy described by Ga1−xAlxAs, where x ranges from 0 to 1. By adjusting the aluminum content, the material’s bandgap can be tuned from that of GaAs (~1.42 eV at room temperature) up to that of AlAs (~2.16 eV). The lattice constant changes with composition but remains closely matched to GaAs for moderate aluminum fractions, enabling high-quality epitaxial growth on GaAs substrates.

The alloy is grown primarily by molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD). Its tunable bandgap and favorable optical and electronic properties make it a key component in GaAs-based heterostructures. AlGaAs layers serve as barrier or cladding layers in quantum wells and laser diodes, creating confinement for electrons and holes in GaAs active regions and improving device performance. The conduction and valence band offsets at GaAs/AlGaAs interfaces form quantum wells that support efficient light emission and carrier transport.

AlGaAs/GaAs heterostructures also enable the creation of two-dimensional electron gases (2DEGs) at the interface, which underpin high-electron-mobility transistors (HEMTs). Doping with n-type or p-type dopants (for example, silicon or beryllium) allows precise control of carrier concentrations. In optoelectronics, AlGaAs is used alongside GaAs in laser diodes and light-emitting diodes, including quantum-well and distributed Bragg reflector (DBR) structures. While versatile, AlGaAs requires careful handling due to the arsenic component and the potential for diffusion at interfaces.