A preference for 3D morphology is shown on all three monolayers, likely as this makes it possible to maximise metal-metal interaction energy by maximising the number of of Cu-Cu bonds and reducing the Cu-Cu distance in each bond. This is also likely why, as seen on MoS 2 , as the cluster size increases, clusters prefer to adsorb above the chalcogen site, even though this is the least stable site for single atom adsorption.