Investigation of the Dependence of Ambipolarity on Channel Thickness for TMDC Based Field Effect Transistors

Abstract

This paper mainly focused on one of the recent attractive electronic devices which is the ambipolar field-effect transistor. Ambipolarity has become important for many applications in recent years. Many factors that cause ambipolarity have been reported in the literature. However, the causes of ambipolarity have not been fully investigated so far. In this study, the degree of ambipolarity was determined as a function of the channel thickness for the WS2 FET device. For the WS2 FET device, the ambipolarity starts from a few layers of channel thickness, and then as the thickness increases, the ambipolarity begins to decrease again. It has been observed that as the thickness increases, the degree of ambipolarity approaches zero. The fact that the degree of ambipolarity approaches zero indicates that the WS2 channel exhibits natural n-type behavior and the ambipolarity effect disappears.

Transfer-free, scalable vertical heterostructure FET on MoS2/WS2 continuous films

“…To apply TMDC FETs to low power and high-performance complementary logic applications, they need to be fabricated in both n-and p-types to reduce fabrication complexity [48]. The polarity of the FETs is determined by the type of charge carriers that can be injected from the source/drain contact into the semiconductor channel [49]. In the literature, thicknessdependent, applied voltages are shown for TMDC-based FETs [50,51].…”