Design of high-speed Ge/GaAs avalanche photodiodes for next-generation photonic integration
Year: 2026
Type: article
Abstract: We present the design and numerical simulation of a top-illuminated Ge/GaAs avalanche photodiode (APD) with a separate absorption, charge, and multiplication structure operating at 1550 nm. The design targets a practical balance between high performance and low manufacturing cost for long-wavelength APDs. Leveraging high carrier mobility and the nearly lattice-matched Ge/GaAs interface, Ge/GaAs APDs provide a path to low-cost, monolithic integration of GaAs with silicon photonic platforms while meeting the demand for high-speed, low-noise photodetectors. Simulations indicate that a 10 μ m-diameter device achieves >30 GHz 3-dB bandwidth, a ∼224 GHz gain–bandwidth product, breakdown voltage of approximately −17 V, and low dark current (1.86 μ A). These results highlight the strong potential of the Ge/GaAs platform for next-generation high-speed photodetectors.
Institutions: University College London, Swansea University
Language: English
Topic: Photonic and Optical Devices
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,325
Awards: G1221392052, Future Compound Semiconductor Manufacturing Hub, EPSRC Compound Semiconductor Manufacturing Hub for a Sustainable Future, A National Research Facility for Epitaxy, QUantum Dot On Silicon systems for communications, information processing and sensing (QUDOS), C-band quantum-dot lasers on monolithically grown Si platform
OpenAlex ID: W7204252999