Charged-impurity free printing-based diffusion doping in molybdenum disulfide field-effect transistors

TL;DR

This paper introduces a charge-impurity free diffusion doping technique for molybdenum disulfide FETs, enhancing mobility by avoiding impurity scattering and enabling better electrical property control.

Contribution

It presents a novel diffusion doping method for CVD-grown MoS2 that eliminates charged impurities, improving device performance over traditional doping methods.

Findings

Over two-fold increase in field-effect mobility

Effective suppression of charged impurity scattering

Selective inkjet doping on contact regions

Abstract

In practical electronic applications, where doping is crucial to exploit large-area two-dimensional (2D) semiconductors, surface charge transfer doping (SCTD) has emerged as a promising strategy to tailor their electrical characteristics. However, impurity scattering caused by resultant ionized dopants, after donating or withdrawing carriers, hinders transport in 2D semiconductor layers, limiting the carrier mobility. Here, we propose a diffusion doping method for chemical vapor deposition (CVD) grown molybdenum disulfide that avoids interference from charged impurities. Selectively inkjet-printed dopants were introduced only on the contact region, allowing excessively donated electrons to diffuse to the channel layer due to the electron density difference. Therefore, diffusion-doped molybdenum disulfide FETs do not have undesirable charged impurities on the channel, exhibiting over two-fold higher field-effect mobility compared with conventional direct-doped ones. Our study paves the way for a new doping strategy that simultaneously suppresses charged impurity scattering and facilitates the tailoring of the SCTD effect.