Transport and Capacitance Properties of Charge Density Wave in Few-Layer 2H-TaS2 Devices

We carefully investigate 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. The nonlinear rather than linear current voltage characteristic of 2H-TaS2 devices is 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 the presence of the CDWs. The conductance-voltage and capacity-voltage measurements are performed simultaneously. At very low ac active voltage, we find 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 gives us a new method to investigate the CDWs.