Dissertation Talk: Device Physics and Materials Properties of Two-Dimensional Semiconductors

Presentation | May 1 | 10:30-11:30 a.m. | Cory Hall, Wang Room / 531

 Sujay Desai, UC Berkeley

 Electrical Engineering and Computer Sciences (EECS)

Two-dimensional (2D) materials like MoS2 and WSe2 are semiconducting analogues to graphene and consist of atomically-thin layers held together by weak van der Waals (vdW) forces. By way of vdW forces, these ultrathin semiconductors can be mechanically exfoliated down to a monolayer of material (~0.7 nm thick). Monolayer 2D materials have large bandgaps, some of which exhibit direct band gap behavior, making them attractive candidates for future electronics and optoelectronics applications.

In this talk, I will discuss the details of 1 nm physical gate length transistors using carbon nanotube gates with a MoS2 channel, emphasizing the unique electrical properties of 2D materials for transistor scaling in the sub-5 nm regime for low-power applications. The next topic will discuss strain engineering of WSe2, with a ~35 X enhancement in photoluminescence resulting from a strain induced indirect-to-direct band gap transition. Finally, I will briefly discuss other results related to large-area gold mediated exfoliation of 2D materials and large-area, bright and transparent monolayer semiconductor based pulsed electroluminescent devices.