Observations of two-dimensional monolayer zinc oxide

•Synthesis of planer ZnO nanostructure.•Observation of multilayered and monolayer ZnO.•DFT calculation of (10-10), (11-20) and (0 0 0 1) planes of ZnO.•Stability of non-polar (10-10) and (11-20) planes of ZnO.

This letter reports the observations of planar two-dimensional ZnO synthesized using the hydrothermal growth technique. High-resolution transmission electron microscopy revealed the formation of a two-dimensional honeycomb lattice and aggregated structures of layered ZnO. The nonpolar (10-10) and (11-20) planes were present in the X-ray diffraction patterns, but the characteristic (0 0 0 1) peak of bulk ZnO was absent. The study found that nonpolar freestanding ZnO structures composed of a single or few layers may be more stable and may have a higher probability of formation than their polar counterparts. The stability of the nonpolar two-dimensional hexagonal ZnO slabs is supported by density functional theory studies.

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