In recent years atomically thin 2D materials like graphene, boron nitride (BN), transition metal dichalcogenides (TMDC) or black phosphorus (BP) have drawn a lot of attention because of their marvelous properties. In this thesis, variety of different two dimensional devices were fabricated and measured to explore the properties of these materials. And the production methods of these devices were also detailedly described and throughly discussed.

Several high quality black phosphorus samples encapsulated with boron nitride thin films were successfully fabricated. An additional strong Raman peak around 5cm^-1 above the A_g¹ mode in the Raman spectrums were observed and investigated. It was believed that this was caused by the strong inter-layer coupling in BP samples, which also resu...[ Read more ]

In recent years atomically thin 2D materials like graphene, boron nitride (BN), transition metal dichalcogenides (TMDC) or black phosphorus (BP) have drawn a lot of attention because of their marvelous properties. In this thesis, variety of different two dimensional devices were fabricated and measured to explore the properties of these materials. And the production methods of these devices were also detailedly described and throughly discussed.

Several high quality black phosphorus samples encapsulated with boron nitride thin films were successfully fabricated. An additional strong Raman peak around 5cm^-1 above the A_g¹ mode in the Raman spectrums were observed and investigated. It was believed that this was caused by the strong inter-layer coupling in BP samples, which also result in its surface atoms to vibrate at a higher frequency than the atoms in its inner layers. And because in theses samples, the BP flakes are sandwiched by atomically smooth BN films, and without interference of exposure to the environment, such signal was able to be pick up and recorded for the first time.

The transport property of monolayer Rhenium Diselenide (ReSe2) were also measured at different temperature with a few devices assembled with van der Waals heterostructure. Because most of time ordinary metals contact with ReSe2 will result in a huge Schottky barrier that makes low temperature measurement almost impossible. So in this work few layer graphene flakes were used as contact electrodes instead. With its tunable Fermi level and high carrier concentration, such gate-tunable graphene electrodes can greatly reduced the Schottky barrier height in theory. And experimental data confirmed this presumption. The devices showed a record high mobility reading at low temperature. More importantly, such method could also be used in other 2D materials’ low temperature characterization. An important implications for future works and potential applications.