Electro-Deposition of Thin Si and Ge Films Based on Ballistic Hot Electron Injection

Apart from the conventional dry process such as chemical vapor deposition (CVD), some electrochemical approaches have been conducted to fabricate thin Si and Ge films. The liquids used to date for electro-deposition of those films are nonaqueous organic electrolytes, 1‐4 tetrachloride solutions (SiCl4, GeCl4), 5,6 ionic liquids, 7‐13 aqueous solutions, 14 and molten salt solutions. 15‐17 In every case, however, deposited films show non-uniform, porous, or contaminant features in structure and composition. Nanocrystalline silicon (nc-Si) diode acts as a planar cold cathode which uniformly emits ballistic hot electrons. 18 The nc-Si emitter is composed of a thin Au (10 nm), an anodized nc-Si layer (∼1 μm), a