Electron channelling contrast imaging techniques were used to study misfit dislocations between single epitaxial layers of Ga0.8In0.2As which had been grown onto (001) GaAs substrates. The epilayer thickness ranged from 25 to 3000nm. Spectral analysis of the electron channelling contrast image intensity traces was used to determine whether the strain fields of individual dislocations overlapped. Appreciable overlapping was first detected at an epilayer thickness of 100nm. This corresponded to the onset of macroscopic strain relaxation.

A.J.Wilkinson: Philosophical Magazine Letters, 1996, 73[6], 337-44