Room-Temperature NO2 Sensing of CVD-Modified WS2-WSe2 Heterojunctions

Abderrahim Moumen, Rajashree Konar, Dario Zappa, Eti Teblum, Gilbert Daniel Nessim, Elisabetta Comini

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7 Scopus citations


Two-dimensional (2D) semiconducting heterojunction chemical sensors are in high demand because of their enhanced response, stability, and selectivity. However, fine-tuning heterojunctions using vapor deposition growth still needs further research. Our present study focuses on the ambient pressure chemical vapor deposition (CVD) synthesis of hexagonal tungsten sulfide-tungsten selenide (WS2-WSe2) p-p heterojunctions (as a 2D-2D arrangement). We use the liquid-phase exfoliation method to disperse bulk WS2 and WSe2 and decorate large flakes of WS2 with smaller WSe2 nanosheets in CVD. Electron microscopy and related surface investigations reveal their homogeneity on drop-casting. Two drops from the exfoliated heterojunction dispersion were drop-cast on a transducer to study the NO2 response and related sensing properties. The sensor showed long-term stability (>2 months), even at high humidity levels (40-90%). The gas-sensing properties of this layered p-p heterojunction-based nanocomposite strongly suggest an affinity toward NO2 gas, leading to improved response, high stability, independent of humidity effects, and high selectivity.

Original languageEnglish
Pages (from-to)7323-7329
Number of pages7
JournalACS Applied Nano Materials
Issue number9
StatePublished - 12 May 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.


G.D.N. thanks the Israel Science Foundation and Israel Prime Ministry Office for the alternative initiative for partial funding of this study under the Israel Research Center for Electrochemical Propulsion (INREP) (Grant: ISF 2797/11). E.C. thanks the support from NATO Science for Peace and Security Programmer (S.P.S.) under grant G5634 AMOXES─“Advanced Electro-Optical Chemical Sensors.” R.K. thanks the International Staff Mobility under the Erasmus+ Program.

FundersFunder number
Israel Prime Ministry Office
NATO Science for Peace and Security ProgrammerG5634
Israel Science Foundation
Israel National Research Center for Electrochemical PropulsionISF 2797/11


    • NO
    • WS−WSe
    • chemical vapor deposition
    • conductometric sensors
    • heterostructures
    • selectivity
    • transition metal di-chalcogenides (TMDCs)


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