Optoelectronics of Multijunction Heterostructures of Transition Metal Dichalcogenides

Woosuk Choi, Imtisal Akhtar, Dongwoon Kang, Yeon Jae Lee, Jongwan Jung, Yeon Ho Kim, Chul Ho Lee, David J. Hwang, Yongho Seo

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Among p-n junction devices with multilayered heterostructures with WSe2 and MoSe2, a device with the MoSe2-WSe2-MoSe2 (NPN) structure showed a remarkably high photoresponse, which was 1000 times higher than the MoSe2-WSe2 (NP) structure. The ideality factor of the NPN structure was estimated to be â1, lower than that of the NP structure. It is claimed that the NPN structure formed a thinner depletion region than that of the NP structure because of the difference of carrier concentrations of MoSe2 and WSe2. Hence, the built-in electric field was weaker, and the motion of the photocarriers was facilitated. These behaviors were confirmed experimentally from a photocurrent mapping analysis and Kelvin probe force microscopy. The work function depended on the wavelength of the illuminator, and quasi-Fermi level was estimated. The surface photovoltage on the MoSe2 region was higher than that on WSe2 because the lower bandgap of MoSe2 induces more electron-hole pair generation.

Original languageEnglish
Pages (from-to)1934-1943
Number of pages10
JournalNano Letters
Volume20
Issue number3
DOIs
Publication statusPublished - 2020 Mar 11

Keywords

  • MoSe
  • Multilayered heterostructures
  • p-n junction
  • Transition metal dichalcogenides
  • Two-dimensional materials
  • WSe

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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