Nanoscale dislocation patterning by scratching in an atomic force microscope

The nature of nanoscratching as a lithographic technique for site-selective generation of dislocations is investigated for use in the growth of nanostructures. Linear arrays of dislocations have been selectively introduced into (001) indium phosphide crystals by dragging a diamond tip in an atomic force microscope. The nature of plastic deformation is found to depend on the scratch direction. For 〈 110 〉 directions, anisotropic butterflylike structures with mostly screw dislocations indicate rotational motion in the vicinity of the advancing tip. For 〈 100 〉 directions, the dislocations do not propagate far from the surface, possibly due to interlocking between dislocations on different slip planes, with a surface morphology suggesting melting of the near surface region by frictional heat. These results indicate that growth of nanostructures should be highly dependent on the direction of the nanoscratch.