Monolithically integrated InAs/InGaAs quantum dot photodetectors on silicon substrates.

Area of Science:

• Semiconductor Physics
• Optoelectronics
• Materials Science

Background:

• Monolithic integration of optoelectronic devices on silicon is crucial for advanced photonic integrated circuits.
• Quantum dot (QD) materials offer unique optical properties suitable for photodetector applications.

Purpose of the Study:

• To demonstrate monolithically integrated InAs/InGaAs quantum dot waveguide photodetectors (PD) on silicon substrates.
• To characterize the performance, including dark current, responsivity, and high-speed response, of these novel QD-on-silicon PDs.
• To explore the potential for on-chip photodetection within a silicon photonics platform.

Main Methods:

• Fabrication of a high-crystalline quality GaAs-on-Si template using aspect ratio trapping, cyclic thermal annealing, and strain-balancing layers.
• Growth of InAs/InGaAs quantum dots within a waveguide structure on the prepared GaAs-on-Si template.
• Characterization of the waveguide photodetector performance, including dark current, internal responsivity, and high-speed response in the O-band spectrum.

Main Results:

• Achieved ultra-low dark current of 0.8 nA and internal responsivity of 0.9 A/W in the O-band.
• Successfully demonstrated high-speed performance and on-chip photodetection for the QD-on-silicon system.
• The waveguide PDs are compatible with existing micro-ring laser platforms for potential integration.

Conclusions:

• Monolithic integration of InAs/InGaAs quantum dot waveguide photodetectors on silicon is feasible and offers excellent performance.
• These integrated photodetectors are suitable for applications such as on-chip optical power monitors and pre-amplified receivers.
• This work advances the development of complex silicon photonic integrated circuits by enabling efficient on-chip photodetection.