Abstract

Elucidation of the microscopic scattering and energy loss processes involved in ultrafast electron dynamics is crucial to the understanding of macroscopic transport in semiconductor systems. In a semiconductor heterostructure system, for example, an electron that crosses the interface between the two materials will scatter from the band minimum of the substrate to a new band in the overlayer, a process that may be complicated by interfacial disorder and interdiffusion. The surface of a semiconductor, in this case the cleaved Ge(111) 2 × 1 surface, provides a particularly interesting model system for the study of such processes. Upon cleavage, one-dimensional chains of π-bonded atoms are formed whose electronic states disperse into the bulk band gap of Ge. The processes that couple bulk excited electrons intestates at the surface arc operative in a wide class of systems.

© 1992 Optical Society of America