SI CAF2 SUPERLATTICES - A DIRECT-GAP STRUCTURE DUE TO INTERFACE STATECOUPLING/

One promising approach for the development of silicon-based light-emit ting devices is the epitaxial growth of Si nanostructures. In this con text, the lattice matched system CaF2/Si/CaF2 as prototype of a well c ontrolled and ordered Si-based system with known microscopic structure is proposed. For this system, a new mechanism is found leading to a d irect band gap based on the coupling of interface states in very thin Si layers.