Statistical characterization of self-assembled colloidal crystals by single-step vertical deposition

We have statistically characterized the self-assembly of multi-layer polystyrene colloidal crystals, using the technique of vertical deposition, with parameters chosen to produce thick layers of self-assembled crystals in one deposition step. The size distribution of domains produced with this technique was seen to follow a log-normal distribution, hinting that aggregation or fragmentation phenomena play a role. In addition, using a lithographically directed self-assembly method, we have shown that the size of multi-layer, continuous crack-free domains in lithographically defined areas can be many times larger than in the surrounding areas. In a single deposition step, we have produced continuous colloidal crystal films of 260 nm diameter polystyrene spheres approximately 30–40 layers thick, with a controllable lateral size of 80–100 μm without lithography, and as high as 250 μm with the lithographic template. This method allows us to suppress the domain size fluctuations and produces mesoscopically thick colloidal crystals of selected size at a selected location.