Local bonding and electronic structure obtained from electron energy loss scattering

Preliminary results using the new high resolution Wien filter spectrometer coupled to the scanning transmission electron microscope show that it is now possible to investigate atomic bonding, and both filled and empty electronic states in inhomogeneous materials with a 1 nm spatial resolution. We show three examples: (1) identification of a 5 nm layer of Si2N2O at a Si/Si3N4 interface using core-loss near-edge fine structure, (2) observation of effects due to changes in the conduction band density of states due to Si-Si bond disorder at the Si/SiO2 interface, and (3) identification of a filled defect electronic state associated with a single misfit dislocation at a GaAs/GaInAs interface. © 1987.