STUDYING THE METAL/LAYERED SEMICONDUCTOR SCHOTTKY INTERFACE USING TEMPERATURE DEPENDENT CURRENT-VOLTAGE MEASUREMENTS AND BALLISTIC ELECTRON EMISSION MICROSCOPY

Abstract

Layered materials based on transition metal dichalcogenides (TMDCs) have attracted a huge amount of attention in recent years as they have been demonstrated to have great potential for next generation electronics. However, one of the key challenges in the field is a lack of know-how to engineer reliable metal/2D semiconductor contacts as a fundamental understanding of the interface is lacking. In this thesis, I have conducted a thorough study of the Au/MoS2 and Au/WS2 Schottky interfaces using temperature dependent current-voltage measurements (I-V-T) and ballistic electron emission microscopy (BEEM). I show that these interfaces are inhomogeneous and can be fit with at least two Gaussian distributions of Schottky barrier heights. Using BEEM, I experimentally verified the presence of the Gaussian distributed Schottky barrier heights. These results are important to guide researchers in the field towards understanding Schottky barriers at the metal/TMDC contacts and the importance of considering Schottky barrier inhomogeneities at the metal/2D-semiconductor interfaces. My work provides important experimental insights to guide researchers in the field towards understanding Schottky barriers at the metal/TMDC contacts. Importantly, the presence of inhomogeneities at the metal/semiconductor interface should be considered in the extraction of device parameters and their impact on device performance should be considered.