Direct Fabrication of Fine Gold Patterns from an Aqueous Solution by a UV Laser

A new strategy for directly fabricating fine gold patterns from an aqueous solution with the help of a UV laser is proposed. The solution contains 90 mmol/L of HAuCl₄ and 280 mmol/L of Na₂SO₃. The process involves two steps. The first step is to create the pattern (seed layer) by irradiating the solution layer spread on the substrate by the UV laser beam. The second step is to immerse the patterned or irradiated substrate in the bulk solution for a certain time to grow the film. A 0.1-μm-thick film is yielded in the irradiated area after 30 min immersion in the solution.