High-temperature negative differential resistance in tungsten diselenide multilayers without heterojunctions

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Conventional complementary metal-oxide-semiconductor (CMOS) devices face limitations.
• Negative differential resistance (NDR) devices offer exotic functionalities.
• Existing NDR devices often rely on heterojunctions, leading to interfacial defects and material constraints.

Purpose of the Study:

• To investigate NDR in WSe2 multilayers without heterojunctions.
• To understand the underlying mechanisms of NDR in this material system.
• To explore the potential for NDR devices in advanced electronics.

Main Methods:

• Fabrication of WSe2 multilayer devices.
• Application of high electrostatic drain and gate bias.
• Temperature-dependent measurements up to 450 K.
• Utilizing hexagonal boron nitride as a dielectric substrate to mitigate oxide trap effects.

Main Results:

• Observed NDR in WSe2 multilayers without heterojunctions.
• Peak-to-valley current ratio (PVCR) of ~1.2 at room temperature, increasing to ~2.3 with hBN substrate.
• Maximum peak current of ~58.4 μA μm⁻¹ achieved.
• Attributed NDR primarily to self-heating effects, not band-to-band tunneling.

Conclusions:

• Self-heating is a key mechanism for NDR in WSe2 multilayers.
• WSe2 multilayers offer a promising platform for NDR devices without complex heterojunctions.
• These findings support the development of NDR-based multi-valued logic devices for next-generation data processing and storage.