GeSn-Based Multiple-Quantum-Well Photodetectors for Mid-Infrared Sensing Applications

Area of Science:

• Photonics and optoelectronics
• Semiconductor materials science
• Infrared spectroscopy

Background:

• Silicon photonics is limited to shorter wavelengths.
• Germanium-tin (GeSn) alloys on silicon enable mid-infrared (MIR) applications.
• GeSn-based photodetectors are crucial for advanced sensing.

Purpose of the Study:

• To theoretically design and simulate GeSn/Ge quantum-well (QW) p-i-n photodetectors (PDs) for MIR applications.
• To enhance photoabsorption and spectral response in the MIR range.
• To evaluate device performance metrics and operational parameters.

Main Methods:

• Heterojunction p-i-n structure with GeSn/Ge QWs and an additional GeSn layer.
• Theoretical modeling and device simulation.
• Analysis of figures of merit: dark current, responsivity, detectivity, NEP, bandwidth, SNR, LDR.

Main Results:

• Extended photodetection up to ~3370 nm.
• High detectivity (>2.5×10⁹ Jones) and low NEP (<2.1×10⁻¹³ WHz⁻⁰.⁵) achieved.
• Significant spectral responsivity (0.86 A/W at 2870 nm, 0.55 A/W at 3300 nm) and 3dB bandwidth (47.8 GHz).

Conclusions:

• The proposed GeSn-based QW p-i-n PDs offer high performance for MIR sensing.
• These devices are promising for next-generation ultra-compact spectroscopic systems.
• The study paves the way for realizing new, high-performance MIR detectors.