Atomic and Electronic Structure of a Dissociated 60° Misfit Dislocation inGexSi(1−x)

Electron energy loss spectroscpy (EELS) spectra and atomic column images were obtained from a dissociated 60° misfit dislocation at the ${\mathrm{Ge}}_x{\mathrm{Si}}_{1-x}$ substrate interface of a strained Si quantum well. Silicon ${2p}_{3/2}$ EELS spectra from the stacking fault show splitting of the $L_1$ conduction band minimum caused by third-neighbor interactions at the fault. Spectra from the 30° dislocation show a similar splitting as well as in-gap defect electronic states. Spectra from the 90° dislocation also show evidence of in-gap states but do not show the $L_1$ splitting. An extended core structure based on a double period pairing reconstruction may be able to explain this lack of $L_1$ splitting.