Date of Award

Spring 5-15-2023

Author's School

McKelvey School of Engineering

Author's Department

Mechanical Engineering & Materials Science

Degree Name

Master of Science (MS)

Degree Type



As silicon-based field-effect transistors (FETs) approach their physical limits with channel lengths approaching 5 nm, the search for new semiconductor materials that can surpass this limit has become urgent. Two-dimensional layered semiconductor nanomaterials, represented by graphene, have emerged as promising candidates due to their unique physical, mechanical, and chemical properties. Unlike traditional silicon-based FETs, two dimensional (2D) layered nanomaterials are held together by van der Waals forces between layers, with no dangling bonds on the material surface, which can effectively address the short-channel effect issue faced by traditional silicon-based FETs. However, unlike traditional silicon-based FETs, which have matured fabrication systems, the semiconductor material acquisition and fabrication techniques for 2D FETs are still under exploration. In this paper, we investigate 2D material FETs and Gate-All-Around (GAA) FETs, including their structural design and fabrication methods, and study their electrical performance. We first introduce various methods for obtaining and transferring 2D semiconductor materials, and describe the specific fabrication process of 2D FET devices, including electrode design, lithography, deposition, and oxide layer growth. Then, we fabricate FETs using 2D MoS2 and test the output characteristics and transfer characteristics of the back-gate and top-gate of the devices, respectively. Finally, we investigate the impact of different metal-semiconductor contacts on device performance, but the devices fabricated did not show the expected improvement, possibly due to the thickness of MoS2 being too thick. To further improve the performance of 2D FETs, we design 2D GAA FETs and analyze and compare two different methods for the transfer oxide layer, each with its advantages and disadvantages, which should be chosen based on specific usage scenarios.


English (en)


Sang-hoon Bae

Committee Members

Katharine Flores Chuan Wang