Quantifying stacking faults and vacancies in thin convectively assembled colloidal crystals

The authors determine the concentration and distribution of stacking faults and vacancies in colloidal crystals between 3 and 11 layers thick grown via convective assembly. The average stacking parameter ⟨α⟩ rises from 0.1 for samples 3 layers thick to 0.8 for ⩾6 layers. For samples ⩾6 layers, the authors also find that the stacking faults are less likely to be near the substrate. The average vacancy concentration is 2.1×10−3 per unit cell. Surprisingly, the layer-averaged vacancy concentration is lowest in the layer nearest the substrate and highest in the next nearest layer.