FORMATION OF ORDERED 2-DIMENSIONAL GOLD COLLOID LATTICES BY ELECTROPHORETIC DEPOSITION

The preparation of ordered two-dimensional (2D) gold colloid lattices using an electrophoretic technique is reported. The lattices can be readily observed by electron microscope and the lattice constants determined by electron diffraction. Using image processing, it can be shown that the gold particles condense into a hexagonal lattice and also that the crystallographic axes of the individual gold particles are randomly oriented. The equilibrium distance between the particles corresponds approximately to the size of the adsorbed stabilizers. The structures are therefore stabilized by short-range steric repulsion and not by a diffuse layer electrostatic barrier, as is normally the case for latex sols. The method is of general interest as a means to prepare monolayer films of nanosized metal or semiconductor particles.