Laterally stitched heterostructure of graphene and molybdenum disulfide for performance enhancement of $MoS_2$ FET

Abstract

2-dimensional materials, especially TMDCs such as $MoS_2, MoSe_2, WS_2, WSe_2$ which consist of one transition metal atom and two chalcogen atoms, have received much attention since grapheme was successfully detached from graphite with scotch tape method. Due to its impressive electrical, optical and mechanical properties, many researchers have researched it. Chemical Vapor Deposition (CVD) enables TMDCs to be synthesized in large area and many researches about applications of TMDCs have been carried out using TMDCs having large area. But electrical property of TMDCs is not sufficient for already commercialized device applications. To overcome the insufficient electrical property, researchers make an effort using heterostructure which consists of two other materials like $MoS_2/WS_2, MoSe_2/WSe_2,$ and $MoS_2/WSe_2$. And also in-plane heterostructure is actively researched. In this thesis, in order to enhance the electrical performance of $MoS_2$ having n-type semiconducting property, laterally stitched heterostructure of graphene and $MoS_2$ was used. The method for making the stitched heterostructure by Chemical Vapor Deposition (CVD) was suggested and Optical analysis, Atomic Force Microscopy, Secondary Electron Microscopy and Transmission Electron Microscopy were used for analyzing the lateral junction part. Also, field effect transistor having graphene as source/drain and MoS2 as channel was fabricated. By comparing with MoS2 field effect transistor, it is proved that laterally stitched heterostructure can make better electrical performance.