  Cluster research so far only dealt with either 3D free clusters or clusters
on substrates with strong electronic coupling at the interface. Preparation of
free and orientated 2D clusters is usually not possible because one of these
conditions generally excludes the other. We demonstrate a new way to grow 2D
clusters of transition metal dichalcogenides which are only weakly bound to the
substrate, i.e. quasi free, but all show the same orientation thus allowing
angle resolved photoemission experiments. In combination with scanning
tunneling microscopy this provides for the first time the possibility to
investigate the correlation between the size of quasi free 2D clusters and its
associated electronic structure. For 2D HfS_2 clusters grown by van der Waals
epitaxy we demonstrate that k_parallel-dispersion of electronic states already
occurs for cluster diameters above ~100 nm.
