Scanning tunneling microscopy (STM) has been used in situ to study the epitaxial growth of CdTe bilayers electrodeposited onto Au single-crystal surfaces. The films were produced by the alternate reductive underpotential deposition of Te and Cd by the electrochemical atomic layer epitaxy (ECALE) technique. The kinetics of electrocrystallization were found to be consistent with an instantaneous 2-D nucleation and growth model. Atomic resolution images of the corresponding first UPD structures of tellurium prior to Cd deposition in a CdSO4 solution have been obtained. Cd/Te bilayer structures formed by Cd UPD on Au(111)-(12×12)Te, Au(110)-c(2×8)Te, and Au(100)-(2×2)Te were Au(111)-(3×3)CdTe, Au(110)-(2×3)CdTe, and Au(100)-c(2×2)CdTe bilayers, respectively. To maintain stoichiometry, bilayer formation was accompanied where necessary (increasing in the order Au(111)-(3×3)CdTe < Au(110)-(2×3)CdTe < Au(100)-c(2×2)CdTe) by a significant rearrangement of the Te structure during bilayer growth. This process was fo...