InPInGaAs

InPInGaAs refers to a semiconductor material system that combines indium phosphide (InP) as a substrate or host and indium gallium arsenide (InGaAs) as an epitaxial alloy. The InGaAs layer is typically engineered to be lattice-matched to InP by adjusting the gallium content, with a common composition around In0.53Ga0.47As that minimizes crystal defects due to lattice mismatch. This lattice matching enables high-quality heterostructures for infrared optoelectronics in the near-infrared range, including wavelengths important for fiber-optic communications.

Crystal structure and properties: Both InP and InGaAs crystallize in the zinc blende structure. InGaAs is a direct-bandgap alloy whose bandgap can be tuned by changing the Ga content, allowing absorption and emission in the near-infrared region around 1.0 to 1.7 micrometers. The lattice-matched In0.53Ga0.47As on InP provides favorable optical and electronic properties for integrated devices, while maintaining good crystal quality and reduced defect densities.

Growth and fabrication: InP/InGaAs heterostructures are typically grown by molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD) on InP substrates. Precise control of composition and layer thickness is essential to achieve lattice matching, high interface quality, and well-defined quantum wells or guiding structures used in devices such as lasers, photodetectors, and modulators. Strain management and defect control are important considerations in device performance.

Applications and context: The InP/InGaAs system is widely used in telecom-focused photonics and integrated photonic circuits. Applications include InP-based laser diodes and photodetectors operating near 1.3–1.55 µm, high-speed photonic modulators, and heterogeneous integrations that combine InP waveguides with InGaAs active regions. The approach leverages mature III–V processing and the compatibility of materials with InP-based infrared optoelectronics.