Two-Dimensional Thickness-Dependent Avalanche Breakdown Phenomena in MoS₂ Field-Effect Transistors under High...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) transition metal dichalcogenides (TMDs) are crucial for next-generation electronics.
• Scaling down 2D electronic devices to the sub-micrometer regime exposes active layers to high lateral electric fields, leading to electrical breakdown.
• Understanding breakdown mechanisms in layered 2D semiconductors is vital for reliable field-effect transistor (FET) applications.

Purpose of the Study:

• To investigate electrical breakdown phenomena in Molybdenum Disulfide (MoS2) field-effect transistors (FETs).
• To explore the role of avalanche multiplication in breakdown under high lateral electric fields.
• To understand how layer thickness influences breakdown characteristics in MoS2.

Main Methods:

• Fabrication of MoS2 FETs with varying layer thicknesses and channel lengths.
• Application of high lateral electric fields to induce and study electrical breakdown.
• Analysis of avalanche multiplication and its dependence on material properties.

Main Results:

• Electrical breakdown in MoS2 FETs originates from avalanche multiplication.
• Modulating the band structure and bandgap energy by adjusting the number of MoS2 layers controls avalanche multiplication.
• This phenomenon is attributed to the quantum confinement effect on the band structure in TMDs.
• A power law relationship was observed between the critical electric field for avalanche breakdown and bandgap energy in both monolayer and multilayer MoS2.

Conclusions:

• Avalanche multiplication is a key mechanism for electrical breakdown in scaled MoS2 FETs.
• Layer thickness offers a method to control breakdown behavior in 2D TMD devices.
• The findings provide insights into the intrinsic electrical properties of layered 2D semiconductors under high electric fields.