Growth-Etch Metal-Organic Chemical Vapor Deposition Approach of WS2Atomic Layers

Assael Cohen, Avinash Patsha, Pranab K. Mohapatra, Miri Kazes, Kamalakannan Ranganathan, Lothar Houben, Dan Oron, Ariel Ismach

Research output: Contribution to journalArticlepeer-review

Abstract

Metal-organic chemical vapor deposition (MOCVD) is one of the main methodologies used for thin-film fabrication in the semiconductor industry today and is considered one of the most promising routes to achieve large-scale and high-quality 2D transition metal dichalcogenides (TMDCs). However, if special measures are not taken, MOCVD suffers from some serious drawbacks, such as small domain size and carbon contamination, resulting in poor optical and crystal quality, which may inhibit its implementation for the large-scale fabrication of atomic-thin semiconductors. Here we present a growth-etch MOCVD (GE-MOCVD) methodology, in which a small amount of water vapor is introduced during the growth, while the precursors are delivered in pulses. The evolution of the growth as a function of the amount of water vapor, the number and type of cycles, and the gas composition is described. We show a significant domain size increase is achieved relative to our conventional process. The improved crystal quality of WS2 (and WSe2) domains wasis demonstrated by means of Raman spectroscopy, photoluminescence (PL) spectroscopy, and HRTEM studies. Moreover, time-resolved PL studies show very long exciton lifetimes, comparable to those observed in mechanically exfoliated flakes. Thus, the GE-MOCVD approach presented here may facilitate their integration into a wide range of applications.

Original languageEnglish
Pages (from-to)526-538
Number of pages13
JournalACS nano
Volume15
Issue number1
DOIs
Publication statusPublished - Jan 26 2021

Keywords

  • 2D materials
  • crystallinity
  • domain size
  • metal-organic chemical vapor deposition
  • time-resolved photoluminescence
  • transition metal dichalcogenides

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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