A thin solid-film deposition scheme is presented based on electron injection from a planar ballistic cold emitter into a metal-salt solution. Under the emitter operation in CuSO4 solutions without using any counter electrodes, thin polycrystalline Cu films are uniformly deposited on the emitting area due to the reduction of Cu2+ ions at the interface. By using the device with patterned emission line windows, a thin Cu nanowire array can be fabricated in parallel. The effect presented here provides an advanced wet processing not only for metallization but also for the deposition of various thin solid films. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3463815] All rights reserved.