Electron Excess Doping and Effective Schottky Barrier Reduction on the MoS2/h-BN Heterostructure

Min Kyu Joo, Byoung Hee Moon, Hyunjin Ji, Gang Hee Han, Hyun Kim, Gwanmu Lee, Seong Chu Lim, Dongseok Suh, Young Hee Lee

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

Abstract

Layered hexagonal boron nitride (h-BN) thin film is a dielectric that surpasses carrier mobility by reducing charge scattering with silicon oxide in diverse electronics formed with graphene and transition metal dichalcogenides. However, the h-BN effect on electron doping concentration and Schottky barrier is little known. Here, we report that use of h-BN thin film as a substrate for monolayer MoS2 can induce ∼6.5 × 1011 cm-2 electron doping at room temperature which was determined using theoretical flat band model and interface trap density. The saturated excess electron concentration of MoS2 on h-BN was found to be ∼5 × 1013 cm-2 at high temperature and was significantly reduced at low temperature. Further, the inserted h-BN enables us to reduce the Coulombic charge scattering in MoS2/h-BN and lower the effective Schottky barrier height by a factor of 3, which gives rise to four times enhanced the field-effect carrier mobility and an emergence of metal-insulator transition at a much lower charge density of ∼1.0 × 1012 cm-2 (T = 25 K). The reduced effective Schottky barrier height in MoS2/h-BN is attributed to the decreased effective work function of MoS2 arisen from h-BN induced n-doping and the reduced effective metal work function due to dipole moments originated from fixed charges in SiO2.

Original languageEnglish
Pages (from-to)6383-6389
Number of pages7
JournalNano Letters
Volume16
Issue number10
DOIs
StatePublished - 12 Oct 2016

Bibliographical note

Publisher Copyright:
© 2016 American Chemical Society.

Keywords

  • Coulomb scattering
  • MoS
  • Schottky barrier height
  • dipole alignment
  • h-BN
  • interface trap density
  • substrate doping

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