Engineering Interfacial Charge Transfer through Modulation Doping for 2D Electronics

TL;DR

This paper explores modulation doping via workfunction engineering in 2D semiconductors, identifying promising material combinations to reduce contact resistance and improve p-type transistor performance for next-generation electronics.

Contribution

It introduces a first-principles approach to identify effective modulation doping materials for 2D semiconductors, expanding beyond traditional choices and providing a roadmap for high-performance p-type transistors.

Findings

High electron affinity materials enable effective p-type doping.

Significant reduction in contact resistance predicted.

New material combinations for 2D transistors identified.

Abstract

Two-dimensional (2D) semiconductors are likely to dominate next-generation electronics due to their advantages in compactness and low power consumption. However, challenges such as high contact resistance and inefficient doping hinder their applicability. Here, we investigate workfunction-mediated charge transfer (modulation doping) as a pathway for achieving high-performance p-type 2D transistors. Focusing on type-III band alignment, we explore the doping capabilities of 27 candidate materials, including transition metal oxides, oxyhalides, and {\alpha}-RuCl3, on channel materials such as transition metal dichalcogenides (TMDs) and group-III nitrides. Our extensive first-principles density functional theory (DFT) reveal p-type doping capabilities of high electron affinity materials, including {\alpha}-RuCl3, MoO3, and V2O5. We predict significant reductions in contact resistance and enhanced channel mobility through efficient hole transfer without introducing detrimental defects. We analyze transistor geometries and identify promising material combinations beyond the current focus on WSe2 doping, suggesting new avenues for hBN, AlN, GaN, and MoS2. This comprehensive investigation provides a roadmap for developing high-performance p-type monolayer transistors toward the realization of 2D electronics.