CRYSTALLINE PARTICLES WITH MULTIPLY TWINNED STRUCTURE IN AMORPHOUS FILMS OF GERMANIUM

Crystalline particles of germanium grown in amorphous films during the vapour deposition of germanium on NaCl substrates have been studied by high resolution electron microscopy. The particles are shown to exhibit a heavily twinned structure which is characterized by mutually oriented fivefold twins accompanied by additional parallel twin lamellae and segments of subgrain boundaries. The particle surface has a rimose outline because of re-entrant faces at the outer terminations of twin boundaries. Growth and structure of the particles are discussed in terms of the nucleation of paracrystalline clusters as well as of twinning processes during growth. A mechanism is proposed by which interlinked multiply twinned structures may originate from crossing of twin lamellae because of internal elastic strains.