Electrocrystallization of Bi on Au(1 1 1) 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.