Optical properties of two-dimensional ZnO nanosheets formed by hot-water treatment of Zn foils

• Facile formation of two-dimensional crystalline ZnO nanosheets by hot-water treating of Zn foils.
• ZnO nanosheets formed by hot-water treatment show excellent photoluminescence.
• Crystallinity of the ZnO nanosheets improved with hot-water treatment time.
• Coalescence of ZnO nanosheets occur after 24-h hot-water treatment because due to Ostwald ripening.

Two-dimensional ZnO nanosheets were formed on metallic Zn foils after hot-water treatment at 90 °C for 4, 8, 12 and 24 h. The photoluminescence spectra of the as-formed ZnO nanosheets exhibit near band edge UV and green emissions; indicating their good crystallinity with presence of oxygen related defects. Raman scattering of the ZnO nanosheets indicated ZnO crystals of high quality were obtained, which was supported by high resolution transmission electron microscope (HR-TEM) results. This low-temperature formation of interconnected two-dimensional ZnO nanosheets with high quality would enable the utilization of substrates with low-thermal stability for optoelectronics applications.