『Abstract
The dissolution of prismatic and rhombohedral quartz surfaces
by KOH/H2O solutions was investigated by
atomic force microscopy. Rates of dissolution of different classes
of surface features (e.g., steps, voids, and dislocation etch
pits) were measured. The prismatic surface etched almost two orders
of magnitude faster than the rhombohedral surface, mostly due
to the difference in the number and the rate of dissolution of
extended defects, such as dislocations. Because of the presence
of imperfect twin boundaries, defect densities on the prismatic
surface were estimated at 50-100μm-2, whereas the rhombohedral
surface possessed only 〜0.5-1.0μm-2, mostly in the
form of crystal voids. Crystal voids etched almost one order of
magnitude faster on the prismatic surface than on the rhombohedral
surface due to differences in the number and the density of steps
formed by voids on the different surfaces. In the absence of extended
defects, both surfaces underwent step-wise dissolution at similar
rates. Average rates of step retreat were comparable on both surfaces
(〜3-5 nm/h on the prismatic surface and 〜5-10 nm/h on the rhombohedral
surface). Prolonged dissolution left the prismatic surface reshaped
to a hill-and-valley morphology, whereas the rhombohedral surface
dissolved to form coalescing arrays of oval-shaped etch pits.』
1. Introduction
2. Experimental
3. Results
3.1. Initial surfaces
3.2. Dissolution of the prismatic surface
3.3. Dissolution of the rhombohedral surface
4. Discussion
5. Conclusions
Acknowledgments
References