High-performance photodetector based on an interface engineering-assisted graphene/silicon Schottky junction.

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Graphene/silicon Schottky junctions are effective photodetectors.
• High dark current in these devices limits weak signal detection capabilities.

Purpose of the Study:

• To engineer the interface of graphene/silicon Schottky photodetectors.
• To reduce dark current and improve performance for weak light detection.

Main Methods:

• Introduction of a thin gadolinium iron garnet (GdIG) film as an interlayer.
• Characterization of photodetector performance, including dark current, light-to-dark current ratio, specific detectivity, broadband absorption, and operational stability.

Main Results:

• A 54-fold decrease in dark current at -2 V bias was achieved.
• High performance in self-powered mode with an I_light/I_dark ratio of 8.2 × 10^6 and specific detectivity of 1.35 × 10^13 Jones at 633 nm.
• Broadband absorption (UV to NIR), fast response (0.15 ms), and long-term stability demonstrated.

Conclusions:

• GdIG thin films effectively suppress dark current by increasing barrier height and passivating the contact surface.
• The novel GdIG interlayer provides a new pathway for developing high-performance photodetectors for weak light applications.
• The device shows practical suitability due to its broadband response, stability, and speed.