[8p-A201-1~7] 15.1 Bulk crystal growth

[8p-A201-7] Colloidal Crystal Growth and Stacking Faults(II)

〇yoshimasa ohki¹, Yuji Nakano¹, Satoshi Kawanaka¹, Hiroki Imai¹, Fumio Uchida¹ (1.Fuji Chemical)

Keywords:Colloidal crystal growth, Stacking fault, Iridescence

Sedimentation grown bulk colloidal crystals are polycrystalline structure composed from bottom thin layer of small crystallites and upper thick bundle of columnar crystallites. In this study, the bottom small crystalline layer was examined by optical microscope and SEM. Almost all iridescence striations of the bottom layer crystallites are parallel to the bottom surface. SEM observations confirmed parallel stacking and fcc dominant ordered structure. These observations indicate the stacking faults and twin structures are parallel to the bottom surface that is six-fold close packed planes are stack parallel to bottom surface. These features of bottom largely differ from upper columnar crystallites where the stacking faults and twin structures are slanted at various angles to the bottom surface as reported at the spring meeting of this society.
The difference in crystalline directions between bottom thin layer and upper bulk body suggests some transition in growth mechanisms between the initial growth stage and later steady growth duration.