Atomic layer deposited Al2O3passivation layer for few-layer WS2field effect transistors

Young Gyu You, Dong Ho Shin, Jong Hwa Ryu, E. E.B. Campbell, Hyun Jong Chung, Sung Ho Jhang

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We have investigated the effect of an Al2O3 passivation layer on the performance of few-layer WS2 FETs. While the performance of WS2 FETs is often limited by a substantial decrease in carrier mobility owing to charged impurities and a Schottky barrier between the WS2 and metal electrodes, the introduction of an Al2O3 overlayer by atomic layer deposition (ALD) suppressed the influence of charged impurities by high-κ dielectric screening effect and reduced the effective Schottky barrier height. We argue that n-doping of WS2, induced by positive fixed charges formed at Al2O3/WS2 interface during the ALD process, is responsible for the reduction of the effective Schottky barrier height in the devices. In addition, the Al2O3 passivation layer protected the device from oxidation, and maintained stable electrical performance of the WS2 FETs over 57 d. Thus, the ALD of Al2O3 overlayer provides a facile method to enhance the performance of WS2 FETs and to ensure ambient stability.

Original languageEnglish
Article number505702
JournalNanotechnology
Volume32
Issue number50
DOIs
StatePublished - 10 Dec 2021

Keywords

  • AlO
  • ambient stability
  • field effect transistor
  • passivations
  • Schottky Barrier
  • WS

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