Indium arsenide (InAs) is a narrow-bandgap III-V compound semiconductor with a direct bandgap of approximately 0.36 eV at room temperature, giving photoresponse out to ~3.5 µm. Its electron mobility (~33,000 cm²/V·s) and ability to form high-quality two-dimensional electron gases (2DEGs) at heterointerfaces make it central to both optoelectronics and quantum devices.
The primary commercial application is infrared detection. InAs-based photodiodes and avalanche photodiodes respond in the SWIR–MWIR range; the material also forms the absorber component in InAs/GaSb type-II superlattice (T2SL) detectors targeting MWIR and LWIR wavelengths. For photonics, InAs quantum dots grown on indium phosphide or, increasingly, on silicon substrates emit at telecom wavelengths (1.3–1.55 µm) and are being pursued as gain media for silicon-integrated lasers — a key bottleneck in co-packaged optics and silicon photonics; Qd Laser works in this space. For quantum computing, InAs 2DEGs and nanowires are platforms for Majorana-based topological qubits, tracked under Topological Qubits (Microsoft Majorana); Novo Holdings Niels Bohr Institute Copenhagen has research programmes in this area. The Mid Ir Photonic Sensing thesis encompasses sensing applications using InAs-containing heterostructures.
Indium Gallium Arsenide (InGaAs) is the primary alloy derivative used at telecom and SWIR wavelengths. Indium Antimonide and Gallium Antimonide are lattice-matched antimonide siblings for longer-wavelength applications.
Frontier
- Can InAs quantum-dot lasers monolithically grown on silicon achieve threshold currents and reliability sufficient for production photonic integrated circuits?
- Will InAs-based topological qubit demonstrations scale to multi-qubit arrays before silicon spin-qubit roadmaps converge?
- Does InAs nanowire growth on Si reach sufficiently low defect density for commercial infrared sensors?