Metal-Semiconductor-Metal GeSn Photodetectors on Silicon for Short-Wave Infrared Applications

Area of Science:

• Optoelectronics
• Materials Science
• Photonics

Background:

• Metal-semiconductor-metal photodetectors (MSM PDs) are crucial for monolithic integration in photonic circuits due to their planar fabrication.
• Germanium-tin (GeSn) alloys offer tunable bandgaps for infrared applications.

Purpose of the Study:

• To design, grow, and characterize GeSn MSM PDs for photonic integrated circuits.
• To investigate the effect of tin incorporation on the optical responsivity of GeSn MSM PDs.

Main Methods:

• Fabrication of GeSn MSM PDs with 4% tin incorporation.
• Optical characterization of spectral responsivity and its dependence on bias voltage.

Main Results:

• GeSn MSM PDs exhibit redshifted optical responsivity extending to 1800 nm, covering telecommunication bands.
• Spectral responsivity increases with bias voltage due to enhanced carrier generation and collection efficiency.

Conclusions:

• GeSn MSM PDs are suitable for photonic integrated circuits and short-wave infrared (SWIR) applications.
• The tunable bandgap of GeSn alloys enables broadband photodetection capabilities.