In general, it is clear that the final adsorption site does not have a large effect on the stability of the Cu cluster, but rather the presence (or absence) of coppercopper bonds determines the stability of the structure on the TMD monolayers. The presence or absence of copper-copper bonds is however largely determined by initial adsorption site so that the initial adsorption site does play a role in determining final cluster stability. Furthermore, there is still a small difference (typically < 0.2 eV) in stability between identical structures on the three different monolayers, with WTe 2 forming the most stable adsorption, and WSe 2 forming the least stable. This indicates that the effect of the chalcogen on adsorption energy is minimal.