Graphene-Insulator-Semiconductor Junction for Hybrid Photodetection Modalities

Area of Science:

• Optoelectronics
• Materials Science
• Semiconductor Physics

Background:

• Traditional optical detectors face limitations in sensitivity and readout capabilities.
• Graphene field-effect transistors (GFETs) offer unique electronic properties for signal amplification.
• Deep depletion techniques in semiconductors can enhance charge collection efficiency.

Purpose of the Study:

• To develop a sensitive optical detector by combining graphene with a deeply depleted semiconductor junction.
• To achieve simultaneous charge integration and localized amplification within a single device.
• To explore the potential of this new architecture for broadband imaging.

Main Methods:

• Fabrication of a deeply depleted graphene-insulator-semiconducting (D²GIS) junction.
• Utilizing photogating of a GFET by carriers generated in a depleted silicon substrate.
• Characterization of responsivity and dynamic range for visible wavelengths.

Main Results:

• Achieved high responsivities up to 2,500 A/W (25,000 S/W).
• Demonstrated a dynamic range of 30 dB.
• Confirmed simultaneous photo-induced charge integration and continuous on-detector readout.

Conclusions:

• The D²GIS detector architecture enables sensitive optical detection with integrated amplification.
• The device principle is transferable to various semiconductor absorbers for broad spectral imaging.
• This technology presents a high-performance paradigm for advanced optical imaging systems.