Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Gallium arsenide (GaAs) is highly valued in RF and microwave electronics because it has significantly higher electron mobility than standard silicon. This means electrons can travel through the GaAs crystal lattice much faster when an electric field is applied. Because the electrons move so quickly, GaAs transistors can switch states rapidly enough to operate effectively at UHF, SHF, and microwave frequencies. This makes them ideal components for high-frequency low-noise amplifiers (LNAs) and oscillators. A key feature of GaAs is that it provides this high-frequency performance while maintaining a very low noise figure. The distractor claiming "higher noise figures" is incorrect because high noise is highly undesirable in receiver circuits.