Intrinsic Electronic Properties of BN-Encapsulated, van der Waals Contacted MoSe2 Field-Effect Transistors

Abstract

Two-dimensional (2D) semiconductors have attracted considerable interest for their unique physical properties. Here, we report the intrinsic cryogenic electronic transport properties in few-layer MoSe2 field-effect transistors (FETs) that are fully encapsulated in ultraclean hexagonal boron nitride dielectrics and are simultaneously van der Waals contacted with gold electrodes. The FETs exhibit electronically favorable channel/dielectric interfaces with low densities of interfacial traps (< 1010 cm−2), which lead to outstanding device characteristics at room temperature, including near-Boltzmann-limit subthreshold swings (65 mV/dec), high carrier mobilities (53–68 cm2⋅V−1⋅s−1), and negligible scanning hystereses (< 15 mV). The dependence of various contact-related parameters with temperature and carrier density is also systematically characterized to understand the van der Waals contacts between gold and MoSe2. The results provide insightful information about the device physics in van der Waals contacted and encapsulated 2D FETs.