Modulation Doping via a 2d Atomic Crystalline Acceptor

TL;DR

This paper demonstrates that -RuCl and layered 2D materials can be used for effective modulation doping, achieving high mobility and charge transfer, with potential applications in nano-electronics and sensing.

Contribution

It introduces -RuCl as a layered crystalline acceptor for modulation doping in various 2D materials, achieving high mobility and charge transfer.

Findings

Achieved high monolayer graphene mobility of 4,900 cm^2/Vs.

Demonstrated large charge transfer to bilayer graphene.

Enabled optical sensing and charge control via twist angle.

Abstract

Two-dimensional (2d) nano-electronics, 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 \textit{ab initio} calculations establish the large work function and narrow bands of $\alpha$-RuCl$_3$ enable modulation doping of exfoliated, chemical vapor deposition (CVD), and molecular beam epitaxy (MBE) materials. Short-ranged lateral doping (${\leq}65\ \text{nm}$) and high homogeneity are achieved in proximate materials with a single layer of \arucl. This leads to the highest monolayer graphene (mlg) mobilities ($4,900\ \text{cm}^2/ \text{Vs}$) at these high hole densities ($3\times10^{13}\ \text{cm}^{-2}$); and yields larger charge transfer to bilayer graphene (blg) ($6\times10^{13}\ \text{cm}^{-2}$). We further demonstrate proof of principle optical sensing, control via twist angle, and charge transfer through hexagonal boron nitride (hBN).