Back Gated Electronic Mapping of 2D Transition Metal Dichalcogenides

Two-dimensional materials have been widely considered as a solution for the further scaling of transistors. The polarity and charge distribution of these materials are critical factors that influence the electrical properties of two-dimensional devices. Current testing methods are limited to postdevice fabrication, preventing the observation of surface charge distribution during device operation. By applying a back gated bias during Kelvin probe force microscopy (KPFM) testing, we successfully obtained the electronic distribution of the channel region in field-effect transistors (FETs) composed of various transition metal dichalcogenides (TMDs), such as MoS2, WSe2, and MoTe2. This method allows for in situ characterization of the intrinsic properties of MoS2 in FETs, independent of the contact influences. Moreover, this approach is applicable to the characterization of N-type, P-type, and ambipolar semiconductor materials, enabling accurate determination of surface potential distribution changes within different FET induced fabrication processes. Our method enables the direct mapping of the electronic distribution and variation trend of the TMD FET materials under biased conditions, providing valuable insight for optimization of the high-performance electronic devices.