A GaSe/Si-based vertical 2D/3D heterojunction for high-performance self-driven photodetectors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials like gallium selenide (GaSe) offer unique electronic properties.
• Vertical heterostructures integrate 2D materials with bulk substrates for novel device architectures.
• Silicon (Si) is a well-established semiconductor for optoelectronic applications.

Purpose of the Study:

• To fabricate and characterize a vertical 2D/3D heterojunction diode using GaSe and Si.
• To investigate the photoresponse properties and performance metrics of the GaSe/Si heterojunction.
• To evaluate the potential of this heterojunction for self-powered optoelectronic devices.

Main Methods:

• Fabrication of a vertical GaSe/Si heterojunction diode.
• Kelvin probe force microscopy (KPFM) for surface potential analysis and band offset evaluation.
• Current-voltage (I-V) measurements to assess diode characteristics.
• Photodetection measurements to determine key performance parameters.

Main Results:

• The GaSe/Si heterojunction exhibited diode-like behavior attributed to a type-II band alignment.
• High photoresponsivity (∼2.8 × 10^3 A W^-1), detectivity (6.2 × 10^12 Jones), and EQE (6011) were achieved at -5 V bias.
• Significant photoresponsivity (6 A W^-1) was observed even at zero bias, indicating self-powered operation.

Conclusions:

• The fabricated GaSe/Si heterojunction diode demonstrates excellent optoelectronic performance.
• The device's ability to operate without external bias highlights its potential as a self-driven photodetector.
• This GaSe/Si heterojunction shows promise for efficient and self-powered optoelectronic applications.