Field-Effect Transistors Built from All Two-Dimensional Material Components

TLDR

Van der Waals bonding between atomically uniform, layered materials allows a unique device architecture where crystalline 2‑D components can be stacked on demand without lattice‑matching constraints. The study aims to demonstrate field‑effect transistors that use heterogeneously stacked two‑dimensional materials for all components—semiconductor, insulator, and metal layers. The authors fabricate devices by stacking MoS₂ as the channel, hexagonal‑BN as the top‑gate dielectric, and graphene as source/drain and gate contacts, and also construct a WSe₂–MoS₂ diode with graphene contacts. The resulting transistor shows n‑type behavior with an ON/OFF ratio >10⁶ and a stable electron mobility of ~33 cm²/V·s even at high gate voltages, while the diode exhibits excellent rectification and low reverse‑bias leakage, underscoring the promise of all‑layered material systems for future electronics.

Abstract

We demonstrate field-effect transistors using heterogeneously stacked two-dimensional materials for all of the components, including the semiconductor, insulator, and metal layers. Specifically, MoS2 is used as the active channel material, hexagonal-BN as the top-gate dielectric, and graphene as the source/drain and the top-gate contacts. This transistor exhibits n-type behavior with an ON/OFF current ratio of >10(6), and an electron mobility of ∼33 cm(2)/V·s. Uniquely, the mobility does not degrade at high gate voltages, presenting an important advantage over conventional Si transistors where enhanced surface roughness scattering severely reduces carrier mobilities at high gate-fields. A WSe2-MoS2 diode with graphene contacts is also demonstrated. The diode exhibits excellent rectification behavior and a low reverse bias current, suggesting high quality interfaces between the stacked layers. In this work, all interfaces are based on van der Waals bonding, presenting a unique device architecture where crystalline, layered materials with atomically uniform thicknesses are stacked on demand, without the lattice parameter constraints. The results demonstrate the promise of using an all-layered material system for future electronic applications.