Cu Intercalation-stabilized 1T'-MoS2 with Electrical Insulating Behavior

TL;DR

This study demonstrates the successful intercalation of copper into high-quality 1T'-MoS2, resulting in an insulating behavior and enhanced stability, which broadens the potential for designing layered material properties.

Contribution

First to identify Cu distribution in 1T'-MoS2 and achieve high crystallinity and thermal stability in intercalated structures.

Findings

Cu occupies tetrahedral interstices aligned with Mo sites

Cu-1T' MoS2 exhibits insulating hopping transport behavior

Large temperature coefficient of resistance of -4 to -2 % K-1

Abstract

The intercalated two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted much attention for their designable structure and novel properties. Among this family, host materials with low symmetry such as 1T' phase TMDCs are particularly interesting because of their potentials in inducing unconventional phenomena. However, such systems typically have low quality and poor stability, hindering further study in the structure-property relationship and applications. In this work, we intercalated Cu into 1T' MoS2 with high crystallinity and high thermal stability up to ~300 oC. We identified the distribution and arrangement of Cu intercalators for the first time, and the results show that Cu occupy partial of the tetrahedral interstices aligned with Mo sites. The obtained Cu-1T' MoS2 exhibits an insulating hopping transport behavior with a large temperature coefficient of resistance reaching -4 ~ -2 % K-1. This work broadens the artificial intercalated structure library and promotes structure design and property modulation of layered materials.