Modulation Doping via a Two-Dimensional Atomic Crystalline Acceptor.

Abstract

Two-dimensional nanoelectronics, plasmonics, and emergent phases require clean and local charge control, calling for layered, crystalline acceptors or donors. Our Raman, photovoltage, and electrical conductance measurements combined with <i>ab initio</i> calculations establish the large work function and narrow bands of α-RuCl₃ enable modulation doping of exfoliated single and bilayer graphene, chemical vapor deposition grown graphene and WSe₂, and molecular beam epitaxy grown EuS. We further demonstrate proof of principle photovoltage devices, control via twist angle, and charge transfer through hexagonal boron nitride. Short-ranged lateral doping (≤65 nm) and high homogeneity are achieved in proximate materials with a single layer of α-RuCl₃. This leads to the best-reported monolayer graphene mobilities (4900 cm²/(V s)) at these high hole densities (3 × 10¹³ cm^-2) and yields larger charge transfer to bilayer graphene (6 × 10¹³ cm^-2).