Dielectric Properties and Ion Transport in Layered MoS₂ Grown by Vapor-Phase Sulfurization for Potential Applications in Nanoelectronics.

ABSTRACT: Electronic and dielectric properties of vapor-phase grown MoS₂ have been investigated in metal/MoS₂/silicon capacitor structures by capacitance-voltage and conductance-voltage techniques. Analytical methods confirm the MoS₂ layered structure, the presence of interfacial silicon oxide (SiO _x ) and the composition of the films. Electrical characteristics in combination with theoretical considerations quantify the concentration of electron states at the interface between Si and a 2.5-3 nm thick silicon oxide interlayer between Si and MoS₂. Measurements under electric field stress indicate the existence of mobile ions in MoS₂ that interact with interface states. On the basis of time-of-flight secondary ion mass spectrometry, we propose OH^- ions as probable candidates responsible for the observations. The dielectric constant of the vapor-phase grown MoS₂ extracted from CV measurements at 100 kHz is 2.6 to 2.9. The present study advances the understanding of defects and interface states in MoS₂. It also indicates opportunities for ion-based plasticity in 2D material devices for neuromorphic computing applications.

SUBMITTER: Belete M 

PROVIDER: S-EPMC6257629 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature