The Role of Transport Agents in MoS2 Single Crystals

TL;DR

This study investigates the electrical, thermoelectric, and thermal properties of MoS2 single crystals grown by CVT, highlighting the influence of transport agents and inherent defects on charge transport and thermal conductivity.

Contribution

It provides a detailed analysis of how different transport agents and growth-induced defects affect MoS2's properties, with comprehensive experimental and theoretical insights.

Findings

Transport agents influence inter-plane resistivity.

Defects from CVT growth affect thermal conductivity.

Strong electron-phonon interaction observed.

Abstract

We report resistivity, thermoelectric power and thermal conductivity of MoS2 single crystals prepared by chemical vapour transport (CVT) method using I2, Br2 and TeCl4 as transport agents. The material presents low-lying donor and acceptor levels, which dominate the in-plane charge transport. Intercalates into the Van der Waals gap strongly influence the inter-plane resistivity. Thermoelectric power displays the characteristics of strong electron-phonon interaction. Detailed theoretical model of thermal conductivity reveals the presence of high number of defects in the MoS2 structure. We show that these defects are inherent to CVT growth method, coming mostly from the transport agent molecules inclusion as identified by Total Reflection X-ray Fluorescence analysis (TXRF) and in-beam activation analysis (IBAA).