M. Kitano et al., GROWTH OF ELECTROCRYSTALLIZED ZNO PARTICLES BY REACTION OF VACUUM-DEPOSITED ZN FILMS WITH DISTILLED WATER, Journal of crystal growth, 152(1-2), 1995, pp. 73-78
Products by electrochemical reaction of vacuum-deposited Zn firms with
distilled water at 20 degrees C are investigated by scanning electron
microscopy (SEM) and an X-ray diffraction method. The time dependence
of the pH of the water indicates three stages of the reaction; the in
itial stage I at pH = 7 for about 20 h, the middle stage II at pH > 7
(Max = 7.7) for about 100 h and the final stage III at pH = 7. In stag
e I etching pits occur as a result of the local cell formation. Each p
it is enclosed by a ZnO bank on the ring margin of 10-100 mu m in diam
eter. Stage II is characterized by the growth of many spindle-like ZnO
particles on the speckles which are traces of the pits of stage I. Th
e ZnO banks dissolve and dendritic beta-Zn(OH)(2) crystals also appear
near the margins. The spindle crystals disappear in stage III. The fo
rmation and morphology of the spindle crystals are described.