FAULTED DIPOLES IN GERMANIUM. A HIGH-RESOLUTION TRANSMISSION ELECTRON MICROSCOPY STUDY.

Faulted dipoles ranging in height from 3 to 12 nm in high-purity Ge have been studied by lattice-fringe and weak-beam transmission electron microscopy techniques. Only intrinsic, Z-shape faulted dipoles were observed. Lattice-fringe images of large faulted dipoles, weak-beam images of faulted dipoles, and weak-beam images of near-edge dislocations yield stacking-fault energies of 78 plus or minus 7, less than equivalent to 82 and 74 plus or minus 14 mJ m** minus **2, respectively. When determined from the height and width of faulted dipoles viewed end-on in lattice-fringe images, the value for the stacking-fault energy calculated from anisotropic elasticity theory increases from 78 to 160 mJ m** minus **2 as the height decreases from 6 to 3 nm.