promoter

aunps

intracerebral hemorrhage

rotor

zno thin

zno films

zno nanorods

zno thin films

spin wave

zno_117448

zno nanowires

zno_68576

azo films

zno nanorod

stories_92885

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vernier

frames reference

fractional fourier transform

Materials Today

Synthesizing two dimensional (2D) nanomaterials with controlled sub-nanometer thicknesses from non-layered crystals presents both significant challenges and vast opportunities. However, mechanical exfoliation techniques and physical/wet chemical deposition processes are widely disadvantageous for applicability to non-layered structures. Here we have utilized a simple self-limiting approach to prepare large sheets of 2D zinc oxide (ZnO) at the metal-melt/air interface. These ultra-thin sheets demonstrated highly crystalline hexagonal structures. The specific ZnO hexagonal sheet thickness and its interaction with the substrate were found to have a critical impact on d 33 . This unusual structure resulted in an exceptionally high out of plane piezoelectricity , yielding a giant value of 80 ± 0.8 pm/V at 2.5 unit-cell thickness for d 33 , which is 5 Zn-O layers in the wurtzite crystal. This out of plane piezoelectricity value is approximately 8 times larger than that of the value for bulk ZnO. Theoretical studies were carried out to elucidate the impact of the thickness and the substrate’s role on the polarization of the layers. The existence of a large piezoelectricity offered by the synergy of the substrate and specific thickness of ultrathin films offers the opportunity for other groups of potentially piezoelectric materials to be explored.

Maximum piezoelectricity in a few unit-cell thick planar ZnO – A liquid metal-based synthesis approach