FABRICATION OF PERIODIC SURFACE STRUCTURES WITH NANOMETER-SCALE SPACINGS

摘要

The periodic stress and strain fields produced by a pure twist grain boundary between two single crystals bonded together in the form of a bicrystal are used to fabricate a two-dimensional surface topography with controllable, nanometer-scale feature spacings (e.g., from 50 nanometers down to 1.5 nanometers). The spacing of the features is controlled by the misorientation angle used during crystal bonding. One of the crystals is selected to be thin, on the order of 5-100 nanometers. A buried periodic array of screw dislocations is formed at the twist grain boundary. To bring the buried periodicity to the surface, the thin single crystal is etched to reveal an array of raised elements, such as pyramids, that have nanometer-scale dimensions. The process can be employed with numerous materials, such as gold, silicon and sapphire. In addition, the process can be used with different materials for each crystal such that a periodic array of misfit dislocations is formed at the interface between the two crystals.