On the dissociation of dislocations in InP

The dissociation of dislocations in undoped and Zn-doped InP single crystals was investigated by transmission electron microscopy. Using the weak-beam technique dissociation widths are obtained ranging from 5 to 15 nm for screw and edge dislocations, respectively. No significant difference of the dissociation widths in the undoped and Zn-doped samples is detected. Using the anisotropic elasticity theory a stacking fault energy of (18.7 ± 1.3) mJm−2 is evaluated. Applying high-resolution transmission electron microscopy the dissociation widths are observed to vary within a wide range for the same type of dislocation. In contrast to the results obtained by the weak-beam technique, α- and β-dislocations of the 60°-type exhibit different dissociation behaviours. The explanation of these observations requires the consideration of additional forces acting at the partial dislocations in the high-resolution specimens.