Conduction bandstructure in strained silicon by spatially resolved electron energy loss spectroscopy

Silicon 2p core absorption near edge fine structure has been obtained by spatially resolved electron energy loss spectroscopy in strained silicon quantum wells. Extraction of the heterojunction band offset as a function of position in the wells appears to be possible with some caution. The band offset has been correlated with atomic composition using annular dark field, Z-contrast imaging. The results suggest that the poor electron mobility, found in one of the wells by standard electrical measurements, resulted from poor carrier screening in the presence of a heterojunction band offset which varied by as much as 50 meV from place to place within the well.