Electrocrystallization of Bi on Au(111) in an acidic chloroaluminate ionic liquid

The electrodeposition of Bi on Au(1 1 1) in an acidic chloroaluminate ionic liquid has been investigated by cyclic voltammetry and in situ STM. Two different UPD processes of Bi have been observed at 1.2 and 0.9 V versus Al/Al(III). Multiple domain structures are found for the first UPD, whereas a uniaxially commensurate monolayer is formed for the second one. More interestingly, high-resolution STM images reveal some meta-stable intermediate superstructure reported here for the first time. The co-adsorption of AlCl4- and Bi adatoms is clearly demonstrated. In the OPD region, different morphologies of Bi crystals have been obtained: a needle-like structure when the potential is swept continuously to 0.6 V, and ultrathin films of Bi when the potential is jumped from 1.3 to 0.4 V. (C) 2007 Elsevier Ltd. All rights reserved.