Atomic Layer MoS2 xTe2(1- x)Ternary Alloys: Two-Dimensional van der Waals Growth, Band gap Engineering, and Electrical Transport

Dong Hwan Kim, Guen Hyung Oh, Ansoon Kim, Chae Ho Shin, Jonghoo Park, Sang Il Kim, Tae Wan Kim

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Ternary alloys in two-dimensional (2D) transition-metal dichalcogenides allow band gap tuning and phase engineering and change the electrical transport type. A process of 2D van der Waals epitaxial growth of molybdenum sulfide telluride alloys (MoS2xTe2(1-x), 0 ≤ x ≤ 1) is presented for synthesizing few-atomic-layer films on SiO2 substrates using metal-organic chemical vapor deposition. Raman spectra, X-ray photoelectron spectra, photoluminescence (PL), and electrical transport properties of few-atomic-layer MoS2xTe2(1-x) (0 ≤ x ≤ 1) films are systematically investigated. The strong PL peaks at 80 K from MoS2xTe2(1-x) (0.45 ≤ x ≤ 0.93) reveal a composition-controllable optical band gap (Eg = 1.55-1.91 eV at 80 K). Electrical transport properties of MoS2xTe2(1-x) alloys, where 0 ≤ x ≤ 0.8 and 0.93 ≤ x ≤ 1, exhibit p-type and n-type semiconducting behaviors, respectively. Remarkably, an increase in the Te composition of a few-atomic-layer MoS2xTe2(1-x) (0 ≤ x ≤ 1) film left-shifts the threshold voltage of a MoS2xTe2(1-x) (0 ≤ x ≤ 1) field-effect transistor. The narrower band gap energies of MoS2xTe2(1-x) films with higher Te content cause a decrease in the on/off current ratios.

Original languageEnglish
Pages (from-to)40518-40524
Number of pages7
JournalACS applied materials & interfaces
Volume12
Issue number36
DOIs
StatePublished - 9 Sep 2020

Keywords

  • MoSTe
  • field-effect transistor
  • metal-organic chemical vapor deposition
  • ternary alloy
  • wafer-scale synthesis

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