Deterministic grayscale nanotopography to engineer mobilities in strained MoS2 FETs

Field-effect transistors (FETs) based on two-dimensional materials (2DMs) with atomically thin channels have emerged as a promising platform for beyond-silicon electronics. However, low carrier mobility in 2DM transistors driven by phonon scattering, remains a critical challenge. To address this issue, we propose the controlled introduction of localized biaxial tensile strain as an effective mean to inhibit electron-phonon scattering in 2DM. Strain is achieved by conformally adhering the 2DM via van-der-Waals forces to a dielectric layer previously nanoengineered with a gray-tone topography. Our results show that a monolayer MoS2 FETs under tensile strain achieves an 8-fold increase in on-state current reaching mobilities of 185 cm2/Vs at room temperature, in good agreement with theoretical calculations. The present work on nanotopographic grayscale surface engineering and the use of high-quality dielectric materials has the potential to find application in the nanofabrication of photonic and nanoelectronic devices.