/ˌɡæl iəm ˈɐr səˌnaɪd/
noun — "the high-speed semiconductor of choice for RF and optoelectronics."
GaAs (Gallium Arsenide) is a III-V compound semiconductor widely used in high-frequency, high-speed, and optoelectronic devices. Its direct bandgap of approximately 1.42 eV allows efficient light emission, making it ideal for LEDs, laser diodes, photodetectors, and solar cells. Additionally, its high electron mobility and saturation velocity outperform silicon in radio frequency (RF) and microwave applications.
Technically, GaAs supports heterostructure and high electron mobility transistor (HEMT) designs, enabling low-noise, high-gain amplifiers and fast-switching circuits. GaAs devices are often fabricated using epitaxial growth methods such as molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD) to create precise crystalline layers. Its wide bandgap allows operation at higher temperatures and voltages than silicon, improving performance in demanding environments.
Key characteristics of GaAs include:
- Direct bandgap: efficient for light emission in LEDs and laser diodes.
- High electron mobility: supports high-speed, high-frequency operation.
- Thermal resilience: operates effectively at elevated temperatures.
- Compatibility with heterostructures: enables advanced quantum wells and transistors.
- RF efficiency: used in microwave and millimeter-wave amplifiers and communication systems.
In practical workflows, GaAs is used in RF front-end modules, power amplifiers, optical communication devices, and solar cells for space and terrestrial applications. Engineers design circuits leveraging GaAs’s speed, direct bandgap, and thermal stability to achieve efficient, high-frequency signal amplification or precise optical emission and detection.
Conceptually, GaAs is like a high-performance sports car in the semiconductor world: fast, efficient, and capable of handling demanding conditions that slow down ordinary silicon devices.
Intuition anchor: GaAs makes high-speed electronics and optoelectronics possible, powering everything from RF amplifiers to laser communications.