MoTe₂ p-n Homojunctions Defined by Ferroelectric Polarization.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials are crucial for next-generation electronics and optoelectronics due to their unique properties.
• Fabricating 2D p-n junctions is essential for advanced device applications.
• Existing carrier modulation methods for 2D materials have limitations.

Purpose of the Study:

• To demonstrate efficient carrier modulation in ambipolar molybdenum telluride (MoTe2) using nonvolatile ferroelectric polarization.
• To create a 2D p-n homojunction at the domain wall of MoTe2.
• To explore the tunable configurations and optoelectronic properties of the MoTe2 p-n junction.

Main Methods:

• Utilized nonvolatile ferroelectric polarization to modulate carrier type in MoTe2.
• Formed a p-n homojunction at the domain wall of MoTe2.
• Investigated device performance using external gate voltage pulses for configuration tuning.

Main Results:

• Achieved a nonvolatile MoTe2 p-n junction with tunable configurations (p-n, n-p, n-n, p-p).
• Demonstrated excellent rectifying characteristics with a high current on/off ratio of 5 × 10^5.
• Observed significant infrared photoresponse with high responsivity (5 A/W), EQE (40%), detectivity (3 × 10^12 Jones), fast response (30 µs), and PCE (2.5%).

Conclusions:

• The ferroelectric-induced MoTe2 p-n junction offers a promising platform for tunable electronic and optoelectronic devices.
• The device exhibits excellent performance as a photodetector/photovoltaic, particularly in the short-wavelength infrared spectrum.
• This technology addresses limitations of current infrared detectors, such as CMOS incompatibility and the need for cryogenic temperatures.