Grain Boundaries in Germanium

Abstract

The relative energies and the boundary orientations of simple tilt boundaries in germanium crystals have been measured. The measurements were made on columnar tricrystals prepared by the modified Czochralski method. The orientations of the columnar tricrystals were either 〈100〉 and 〈111〉 isoxial or (100) isoplanar. The relative grain boundary energies were measured as a function of the angular misorientation θ between two grains. The crystallographic orientations of the grain boundary plane were also determined. It was found that the relative energy of 〈100〉 and 〈111〉 tilt boundaries up to about 15° of misorientation changes with misorientation as predicted by Read and Shockley's theory. For larger angles of misorientation, the grain boundary energy is essentially independent of the angle of misorientation. This indicates a significant but continuous change in boundary structure at the transition region. Additional evidence for the difference in the structure of low- and high-angle tilt boundaries was found in the apparent strong dependence of the energy of low-angle boundaries on the boundary orientation. Low-angle (100) twist boundaries were not observed.