Electronically Decoupled Films of InSe Prepared by van der Waals Epitaxy: Localized and Delocalized Valence States

Submonolayer to several monolayer thick films of the layered semiconductor InSe were deposited on highly oriented pyrolytic graphite by van der Waals epitaxy and probed by energy dependent angle resolved photoelectron spectroscopy. The layers show a transition from two-dimensional bands with atomiclike states to molecularlike states localized along the c direction normal to the surface. The extended band structure showing band dispersion was observed for thicker films