Nanofabulous Seminar: Ferroelectricity in Two-Dimensional Heterobilayers

Two-dimensional (2D) materials with out-of-plane (OOP) ferroelectric and piezoelectric properties are highly desirable to realize ultrathin ferro- and piezo-electronic devices. We demonstrate unexpected OOP ferroelectricity and piezoelectricity in untwisted, commensurate, and epitaxial MoS2/WS2 heterobilayers synthesized by scalable one-step chemical vapour deposition (CVD). The modulation of tunneling current by ~103 times in ferroelectric tunnel junction (FTJ) devices by changing the polarization state of MoS2/WS2 heterobilayers was demonstrated. Our results are consistent with density functional theory, which shows that symmetry breaking and interlayer sliding give rise to unexpected properties without invoking twist angles or Moiré domains [1].

Ref: [1] Lukas Rogée et al., Science 376, 973–978 (2022)



Relationship between second harmonic generation intensity and vertical stacking angleq. Dark triangles are labelled 2H-like and bright triangles 3R-like.




Professor Shu Ping Lau
Department of Applied Physics, The Hong Kong Polytechnic University

2:00pm, 27/02/2024
Melbourne Centre for Nanofabrication
151 Wellington Road, Clayton, 3168

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Meeting ID: 880 2472 4631 and passcode: 865805

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