Indium gallium arsenide (In₍ₓ₎Ga₍₁₋ₓ₎As) is a III-V ternary alloy whose bandgap is continuously tunable from 0.36 eV (pure InAs) to 1.42 eV (pure GaAs) by varying the indium fraction x. The lattice-matched composition to indium phosphide (x ≈ 0.53, bandgap ≈ 0.74 eV) is the single most commercially important III-V photodetector material, with photoresponse spanning roughly 0.9–1.7 µm — the short-wave infrared (SWIR) window.
The dominant application is SWIR photodetection. InGaAs p-i-n and avalanche photodiodes (APDs) are the standard receiver in fibre-optic telecommunications, LIDAR ranging, and optical coherence tomography. In focal-plane array (FPA) form, InGaAs cameras enable night-vision under starlight, machine-vision through fog, semiconductor inspection, and hyperspectral imaging. High-volume producers include Albis Optoelectronics, Sensors Unlimited Collins Aerospace, Princeton Infrared Technologies, and Swir Vision Systems. The InGaAs SWIR Sensors concept page covers the detector-technology layer in more detail.
Frontier
- Can colloidal or epitaxial InGaAs on silicon reach sufficient dark-current performance to displace bulk-grown wafer detectors in consumer SWIR cameras?
- What indium composition and strain engineering is required to push single-photon detection efficiency above 90% at 1550 nm in InGaAs SPADs?
- Does extended-wavelength InGaAs (high-In, lattice-mismatched) become cost-competitive with HgCdTe for commercial MWIR focal-plane arrays?