Multi-layer MoTe2 p-channel MOSFETs with high drive current

Abstract

Transition metal dichalcogenides (TMDs) are interesting materials for electronic applications due to their layered crystal structure, which offers the potential to realize transistors with ultra-thin or even monolayer body thicknesses [1]. Unlike single-layer graphene, TMDs typically have band gaps in the range of 1-2 eV, making them suitable for logic transistor applications [2]. MoTe2 is an ideal material for p-MOSFETs due to its low electron affinity and relatively narrow band gap of ~ 1 eV [3]. MoTe2 is also of interest for realizing tunneling field effect transistors (TFETs) with highly-staggered or broken-gap band alignments [4], particularly when integrated with high electron affinity TMDs, such as SnSe2 [5]. However, to date, only n-MOSFETs and ambipolar transistors have been demonstrated experimentally using thin-film MoTe2 [6, 7]. In this work, we report the characteristics of p-MOSFETs using exfoliated MoTe2 with Pd contact metallization. We characterize the properties of these backgated devices as a function of temperature and extract the Schottky barrier height of the Pd metallization. We also show that strong p-type doping occurs in these devices after prolonged exposure to ambient atmosphere, resulting in p-MOSFETs with linear contacts and drive current approaching 100 uA/um.