Young Hee Lee

SungKyunKwan University

What are the unique features of 2D-layered materials?
Abstract No. : PL_01
Date & Time : Dec. 7 (Mon), 13:05-13:50
Place : Ballroom 1
Name : Young Hee Lee
Affiliation : SungKyunKwan University
Chair : Han Woong Yeom (IBS, POSTECH)
In addition to metallic graphene monolayer, insulating hexagonal-BN monolayer and semiconducting layered transition metal dichalcoginides (LTMDs) are new classes of transparent and flexible materials, which can be used as essential components of transistors for soft electronics. While large-area graphene is available in a meter-scale, synthesis of large area monolayer h-BN and LTMDs are still a long way to realize. These materials have known to exhibit exotic physical and chemical phenomena which have never been accessed so far with 3D materials. I will demonstrate some key concepts of 2D materials why they differ from 3D and show some examples of some new phenomena that emerge uniquely in 2D materials in this talk. We will also demonstrate that thin MoTe2 revealed a reversible phase transition from 2H to 1T’ at around 650-900oC depending on Te-rich conditions. We will further demonstrate that the phase transition of MoTe2 can be provoked by several robust parameters such as laser irradiation and strain. The problematic Ohmic contact was realized by phase patterning of the contact area at source and drain positions with laser irradiation. We further demonstrate that even the phase transition temperature can be reduced to room temperature by applying a tensile strain of ~0.2%.