MoS$_{2}$ Field Effect Transistors with different polarity: study of electrode work functions

The transfer characteristics of Molybdenum disulfide (MoS$_{2})$ field effect transistors (FETs) depend on the Schottky barrier formed between the metal electrode and the semiconducting MoS$_{2}$. We obtained p-type behavior for Pd-contacted MoS$_{2}$ FETs and n-type with both Au and Nb [1] contacts. We study the work function of these electrode metals to understand their effect on the Schottky barrier and therefore the polarity of the MoS$_{2}$ FETs. The work function of the above metals is measured using a non-contact Kelvin Probe technique under different ambient conditions. We will discuss the observed n-type and p-type behavior of MoS$_{2}$ FETs in relation to the measured metal work functions.\\[4pt] [1] M. Fontana, T. Deppe, A. Boyd, M. Rinzan, A. Liu, M. Paranjape, P. Barbara, Photovoltaic effect in gated MoS2 Schottky junctions, in, arXiv:1206.6125v1 [cond-mat.mtrl-sci]