Gate Controlled Photocurrent Generation Mechanisms in High-Gain In₂Se₃ Phototransistors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Device Physics

Background:

• Photodetectors often exhibit trade-offs between response speed and sensitivity due to simultaneous photocurrent generation mechanisms.
• High gain processes in van der Waals photodetectors can limit device response times as they are difficult to switch off.

Purpose of the Study:

• To investigate the potential of Indium Selenide (In2Se3) in developing advanced photodetectors.
• To demonstrate tunable control over photocurrent generation mechanisms in photodetectors.
• To achieve high gain and fast response times in a single photodetector device.

Main Methods:

• Fabrication of photodetectors utilizing layered In2Se3.
• Characterization of photocurrent generation mechanisms under varying back gate voltages.
• Analysis of device performance, including gain and detectivity.

Main Results:

• Demonstrated complete modulation of a photogating mechanism in In2Se3 photodetectors.
• Achieved a transition from a gate-modulated photogating effect to a gate-independent photoconduction.
• Observed ultrahigh gains of (9.8 ± 2.5) × 10^4 A/W and detectivities of (3.3 ± 0.8) × 10^13 Jones.

Conclusions:

• In2Se3 is a promising material for high-performance photodetectors.
• The developed photodetectors offer tunable photocurrent generation, balancing gain and speed.
• In2Se3-based devices represent a significant advancement in 2D material photodetection.