Morphology dependent field emission from copper sulfide nanosheet arrays tailored with electrolyte concentrations in anodic oxidation process

Abstract Vertically oriented copper sulfide nanosheet arrays were successfully fabricated by a simple and manageable electrochemical anodization method at room temperature. By controlling and adjusting the concentrations of sodium sulfide electrolyte to be 0.1 M, 0.5 M, 1.0 M and 1.5 M, respectively, the morphologies of copper sulfide nanosheets (average size, thickness or density of sharp edges) could be well tailored and be more optimized for applications in field emission (FE). As the results showed, for optimal nanostructure of such copper sulfides nanosheet arrays, its turn-on field could be lowered to 2.0 V/μm and the field emission current density would reach up to 4.1 mA/cm2 under an applied field of 6.4 V/μm, and also it can exhibit excellent field emission stability, with a degradation lower than ±4% and a huge field enhancement factor of 8327.