Study of the Band Alignment between Atomic-Layer-Deposited High-kappa Dielectrics and MoS2 Film

Abstract

In this study, we determined the energy-band alignment of various amorphous high-kappa dielectrics (Al2O3, HfO2, ZrO2, and TiO2) that were deposited on amolybdenum disulfide (MoS2) film through atomic layer deposition by using high-resolutionX-ray photoelectron spectroscopy. The uniformity and continuity of the MoS2 films were inspected by physical characterizations. The roughness of MoS2 film deposited by chemical vapor deposition was evaluated using atomic force microscopy. Moreover, cross-sectional transmission electron microscopy images confirmed that all high-kappa dielectrics were uniformly and continuously deposited on the MoS2 film, leading to superior high-kappa dielectric-MoS2 stacks. An abrupt interface between the high-kappa dielectrics and MoS2 film was also observed. Finally, the valance and conduction band offsets between the Al2O3, HfO2, ZrO2, and TiO2 and the MoS2 film interface were measured to be 3.14, 1.81, 1.56, and 0.18 eV and 2.36, 1.77, 1.88, and 1.68 eV, respectively. Our study demonstrated the direct deposition of numerous commonly used high-kappa dielectrics on top of a MoS2 film. This top-down scheme is very useful for applying two-dimensional materials to complementary metal-oxide-semiconductor field-effect-transistor circuits. (C) 2018 The Electrochemical Society.