Transport and Capacitance properties of Charge Density Wave in few layer 2H-TaS2 Devices

TL;DR

This study explores the transport and capacitance behaviors of few-layer 2H-TaS2 devices exhibiting charge density waves, revealing their semiconducting nature at low temperatures and introducing capacitance-voltage measurements as a new method to analyze CDW depinning.

Contribution

It provides new insights into the electrical properties of few-layer 2H-TaS2 and demonstrates capacitance-voltage measurements as a novel approach to study charge density waves.

Findings

CDW transition temperature varies among devices

Semiconducting behavior observed at low temperatures

Capacitance-voltage measurements match hysteresis loops

Abstract

We carefully investigated the transport and capacitance properties of few layer charge density wave (CDW) 2H-TaS2 devices. The CDW transition temperature and the threshold voltage vary from device to device, which is attributed to the interlayer interaction and inhomogeneous local defects of these micro-devices based on few layer 2H-TaS2 flakes. Semiconductivity rather than metallic property of 2H-TaS2 devices was observed in our experiment at low temperature. The temperature dependence of the relative threshold voltage can be scaled to (1- T / Tr )^0.5+delta with delta=0.08 for the different measured devices with presence of the CDWs. The conductance-voltage and capacity-voltage measurements were performed simultaneously. At very low ac active voltage, we found that the hysteresis loops of these two measurements exactly match each other. Our results point out that the capacity-voltage measurements can also be used to define the threshold depinning voltage of the CDW, which give us a new method to investigate the CDWs.