Controllable 2H-to-1T' phase transition in few-layer MoTe₂

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) transition metal dichalcogenides (TMDs) possess multiple structural phases, offering unique physical properties.
• These properties present opportunities for advanced device applications, extending beyond materials like graphene.

Purpose of the Study:

• To demonstrate a method for inducing phase transitions in few-layer molybdenum ditelluride (MoTe2) using laser irradiation.
• To investigate the influence of laser power and irradiation duration on the structural phase of MoTe2.

Main Methods:

• Controlled laser irradiation of few-layer molybdenum ditelluride (MoTe2).
• Systematic variation of laser power and irradiation time to study phase transition dynamics.
• Post-irradiation thermal annealing to assess phase stability.

Main Results:

• Laser irradiation successfully triggered the 2H-to-1T' phase transition in few-layer MoTe2.
• The accumulated heating effect was identified as the primary driver for the phase transition.
• Precise control over laser parameters allowed for tuning MoTe2 phases to 2H, 2H + 1T', or 1T'.
• Thermal annealing confirmed the irreversibility of the laser-induced transition, attributed to Te vacancy formation.

Conclusions:

• Laser irradiation offers a controllable route to manipulate the structural phases of 2D MoTe2.
• The findings highlight the role of localized heating and defect formation in driving irreversible phase transitions.
• This work supports the development of high-performance nanoelectronic and optoelectronic devices utilizing 2D TMDs.