Pulsed Laser Deposition Assisted van der Waals Epitaxial Large Area Quasi-2D ZnO Single-Crystal Plates on Fluorophlogopite Mica

There are still challenges in growth of transferable large area orientated ultrathin high-melting-point metal oxide single crystals with conventional methods. Herein, a new pathway to produce high quality single-crystal ZnO nanoplates with more than 400 mu m crystal size is revealed by using the van der Waals epitaxy (vdWE) combined with pulsed laser deposition (PLD) method on fluorophlogopite mica. The quasi-2D ZnO plates as thin as 5 nm on fluorophlogopite mica without transition layer are achieved, showing an excellent thickness and orientation control while maintaining the excellent crystalline. ZnO nanoplates grown on conducting graphite and insulating hexagonal boron nitride (h-BN) 2D substrates are also obtained through PLD assisted vdWE. The transfer of 15 nm thick quasi-2D ZnO plates with 8 mm x 8 mm area onto a SiO2/Si substrate is successfully demonstrated. Based on the ZnO nanoplates, semitransparent self-powered ultraviolet (UV) photodetectors and light-emitting diodes centered at 400 nm UV region are demonstrated. This research highlights that the PLD assisted vdWE method is a fascinating way to fabricate high coverage ultrathin 2D ZnO plates with precisely thickness control for optoelectronic applications and may have enormous inspiration for other 2D nanomaterials growth.