Effect of Metal Coupling on Schottky Barrier Height Extraction

This paper investigates the impact of metal contact coupling strength and Fermi energy on temperature-dependent currents and the extraction of Schottky barrier height. As the scaling of contact length becomes increasingly important, understanding the role of metal coupling in establishing good contacts with low-dimensional materials is crucial. A coupled mode-space NEGF approach with Schottky contacts that accounts for the coupling strength between metal and carbon atoms is utilized to simulate the temperature-dependent currents in CNT devices. For weakly coupled contacts, the effective Schottky barrier height at the on-state is comparable to the flat band value, while for strongly coupled contacts, it can be reduced to the point of becoming negative, implying distinct degrees of dominance between thermal-assisted and direct tunneling. These findings may guide experimental measurements and inform strategies to achieve high-quality contacts with low-dimensional materials for scaled devices.