Short-wavelength infrared (SWIR) photodetector based on multi-layer 2D GaGeTe.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Theoretical studies suggest 2D GaGeTe crystals offer high infrared detection sensitivity and ultrafast operation due to small bandgap and high carrier mobility.
• Experimental exploration of GaGeTe for infrared photodetection remains limited, leaving its potential unverified.

Purpose of the Study:

• To experimentally demonstrate a short-wavelength infrared (SWIR) photodetector utilizing multilayer (ML) GaGeTe field-effect transistors (FETs).
• To characterize the performance of ML GaGeTe FETs for SWIR photodetection, including responsivity, noise equivalent power, and frequency response.

Main Methods:

• Fabrication of ML GaGeTe FETs.
• Characterization of device electrical properties (p-type behavior, mobility).
• Measurement of photodetection performance under 1310 nm illumination (responsivity, NEP).
• Analysis of frequency response using intensity-modulated light at 1310 nm.

Main Results:

• Fabricated devices exhibited p-type behavior with hole mobility of 8.6–20 cm²V^-1s^-1.
• Photodetectors (65 nm flake thickness) achieved high photoresponsivity (up to 57 A/W) and low noise equivalent power (0.1 nW/Hz^1/2) at 1310 nm and V_ds=2 V.
• Devices demonstrated a frequency response up to 100 MHz with a 3dB cut-off frequency of 0.9 MHz, with response dependent on bias and gate voltages.

Conclusions:

• The experimental results validate the potential of multilayer GaGeTe for highly sensitive and ultrafast SWIR photodetection.
• This work provides crucial experimental data, stimulating further research and development of GaGeTe-based optoelectronic devices.
• The demonstrated ML GaGeTe FETs show promise for practical applications in advanced infrared sensing technologies.