Using scanning tunneling microscopy, two systems of Fe deposition on clean Ge(1 1 1)-c(2 x 8) surface and surfaces with a (root 3- x root 3)R30 degrees Ag-Ge buffer layer were compared. Complex surface alloy structures were easily formed on Fe/Ge systems through annealing at 300-650 K. On clean Ge(1 1 1) surfaces, similar surface morphology evolution was observed when two different amounts of Fe were deposited. To reduce the complexity, (root 3- x root 3)R30 degrees Ag-Ge interfaces were used as buffer layers. The growth morphologies differed in the presence and absence of the buffer layers. During annealing at 570 K, (2 x 2) reconstruction platform islands were formed in the Fe-Ge system, which transformed to three-dimensional (3D) islands at 640 K. With Ag buffer layer, only nanoparticle growth occurred and 3D islands were formed early at 570 K. Generally, root 19 ring clusters increased to break the order c(2 x 8) reconstruction by increasing the temperature and disappeared at 640 K in a Fe-Ge system, but only root 7 ring clusters appeared at 390 K with (root 3- x root 3)R30 degrees Ag-Ge buffer layer. (C) 2015 Elsevier B.V. All rights reserved.