The assembly of one- and two-dimensional crystals from suspensions of latex or silica microspheres subjected to an alternating electric field in a gap between planar electrodes on a surface is discussed. These crystals having areas above 25 mm2 are oriented without the need for micropatterned templates. The particles are accumulated on the surface between the electrodes due to the field gradients, align into rows along the field direction and are crystallized into hexagonal arrays. The electrostatic repulsion is used to control the lattice spacings.
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