Reconfigurable Phototransistors Driven by Gate-Dependent Carrier Modulation in WSe₂/Ta₂NiSe₅ van der Waals...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Reconfigurable field-effect transistors (RFETs) offer advantages over conventional complementary metal-oxide semiconductor transistors for electronic and optoelectronic circuits.
• A key challenge for RFETs is their low on/off current ratio, limiting practical applications.

Purpose of the Study:

• To address the limitations of RFETs by proposing a novel van der Waals heterojunction (vdWH) transistor.
• To demonstrate a switchable polarity configuration and bidirectional rectification using a WSe2/Ta2NiSe5 vdWH transistor.

Main Methods:

• Fabrication of a van der Waals heterojunction (vdWH) transistor using WSe2 and Ta2NiSe5 materials.
• Modulation of device characteristics using back-gate voltage and source-drain voltage.
• Analysis of energy band structures to understand device operation.

Main Results:

• The WSe2/Ta2NiSe5 vdWH transistor achieved switchable polarity and bidirectional rectification, functioning as a gate-controlled bidirectional half-wave rectifier.
• Tunable positive/negative photovoltaic responses and gate-voltage-dependent photodetector position reversal were observed.
• The device's reconfigurability was attributed to carrier blockage from a type-I band structure and gate-modulated Schottky barriers.

Conclusions:

• The developed reconfigurable WSe2/Ta2NiSe5 vdWH transistor effectively overcomes the low on/off current ratio limitation.
• The device exhibits promising multifunctional optoelectronic capabilities, including tunable photovoltaic responses and gate-controlled rectification.
• This vdWH transistor holds significant potential for advanced optoelectronic device applications.