Full energy spectra of interface state densities for n- and p-type MoS2 field-effect transistors

Abstract

Two-dimensional (2D) layered materials are promising for replacing Si to overcome the scaling limit of recent ~5 nm-length metal-oxide-semiconductor field-effect transistors (MOSFETs). However, the insulator/2D channel interface severely degrades the performance of 2D-based MOSFETs, and the origin of the degradation remains largely unexplored. Here, we present the full energy spectra of the interface state densities (Dit) for both n- and p- MoS2 FETs, based on the comprehensive and systematic studies, i.e., thickness range from monolayer to bulk and various gate stack structures including 2D heterostructure with h-BN as well as typical high-k top-gate structure. For n-MoS2, Dit around the mid gap is drastically reduced to 5*10^11 cm-2eV-1 for the heterostructure FET with h-BN from 5*10^12 cm-2eV-1 for the high-k top-gate MoS2 FET. On the other hand, Dit remains high, ~10^13 cm-2eV-1, even for the heterostructure FET for p-MoS2. The systematic study elucidates that the strain induced externally through the substrate surface roughness and high-k deposition process is the origin for the interface degradation on the conduction band side, while sulfur-vacancy-induced defect-states dominate the interface degradation on the valance band side. The present understanding on the interface properties provides the key to further improving the performance of 2D FETs.

References in corpus (9)

• Anomalous Lattice Vibrations of Single and Few-Layer MoS2
• Probing the Electron States and Metal-Insulator Transition Mechanisms in Atomically Thin MoS2 Based on Vertical Heterostructures
• Carrier statistics and quantum capacitance effects on mobility extraction in two-dimensional crystal semiconductor field-effect transistors
• Band tail interface states and quantum capacitance in a monolayer molybdenum disulfide field-effect-transistor
• Pinpoint pick-up and bubble-free assembly of 2D materials using PDMS/PMMA polymers with lens shapes
• Influence of the density of states of graphene on the transport properties of graphene/MoS2/metal vertical field-effect transistors
• Buffer Layer Engineering on Graphene via Various Oxidation Methods for Atomic Layer Deposition
• Transport properties of the top and bottom surfaces in monolayer MoS2 grown by chemical vapor deposition
• Experimental detection of active defects in few layers MoS2 through random telegraphic signals analysis observed in its FET characteristics

Cited by in corpus (3)

• All 2D Heterostructure Tunnel Field Effect Transistors: Impact of Band Alignment and Heterointerface Quality
• Understanding the Memory Window Overestimation of 2D Materials Based Floating Gate Type Memory Devices by Measuring Floating Gate Voltage
• Understanding interface properties in 2D heterostructure FETs