Nano-floating gate memory devices with ZnO nano-crystals as charge storage layers are fabricated,and the influence of post-deposition annealing temperature and thickness of the ZnO layer are investigated.Atomic force microscopy and scanning electron microscopy reveal the morphology of discrete ZnO nano-crystals.For capacitance-voltage measurements,it is found that the memory device with 1.5 nm ZnO and annealed at 700℃ shows a larger memory window of 4.3 V (at ±6 V) and better retention characteristics than memory devices with 2.5nm ZnO or annealed at other temperatures.These results indicate that the nano-floating gate memory with ZnO nano-crystals can obtain good trade-off memory properties.