Electrodeposition of Nanosized Germanium from GeBr[sub 4] and GeCl[sub 4] in an Ionic Liquid

Germanium films several micrometers in thickness were electrodeposited for the first time at room temperature from the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, saturated with either or Cyclic voltammograms of both systems are similar and exhibit two apparently irreversible diffusion-controlled reduction peaks. The more positive first process is correlated to the Ge(IV)/Ge(II) redox couple, the second process to Ge(II)/Ge(0). The initial stages of the overpotential deposition start with the formation of nanoclusters in both systems, shown with in situ scanning tunneling microscopy. Qualitative X-ray photoelectron spectroscopy analysis shows that the micrometer thick black bulk deposits composed of nanoclusters contain mostly elemental germanium with a small amount of bromide or chloride at the surface, respectively.