Strongly enhanced electromechanical coupling in atomically thin transition metal dichalcogenides

Md Farhadul Haque, Peter Snapp, Jin Myung Kim, Michael Cai Wang, Hyung Jong Bae, Chullhee Cho, Sung Woo Nam

Research output: Contribution to journalArticlepeer-review

Abstract

Flexoelectricity in thin films has emerged as an effective electromechanical response owing to appealing scaling law and universal existence. However, current studies show limited out-of-plane converse flexoelectric effect (CFE) of ultra-thin transition metal dichalcogenides (TMDs) when compared to their conventional in-plane piezoresponse. Here, we report converse flexoresponse of atomically thin TMDs such as molybdenum disulfide (MoS2) and tungsten diselenide (WSe2) which exceeds their intrinsic in-plane piezoresponses. Our piezoresponse force microscopy (PFM) measurements revealed strongly enhanced CFE of the atomically thin MoS2 and WSe2 than their bulk counterpart (∼700% enhancement in MoS2, ∼400% enhancement in WSe2). We observed an anomalous reduction in converse flexoresponse in the monolayer structure attributed to a puckering deformation. By inducing a built-in in-plane tension to reduce puckering, we estimated the CFE of monolayer WSe2 to be 8.14 pm/V, the highest among the atomically thin TMDs.

Original languageEnglish (US)
JournalMaterials Today
DOIs
StateAccepted/In press - 2021

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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