EX SITU ATOMIC FORCE MICROSCOPY STUDIES OF SURFACE MORPHOLOGY ON {001} FACES OF MMTWD CRYSTALS

Surface morphology of the {001} faces of MMTWD crystals grown from by the temperature-lowering method has been studied. Monolayer and multilayer steps elongate along the a direction, which is determined by the crystal structure. Apart from that, the elementary steps have narrower terraces than the bunched ones, which may be resulting from the faster growth rates of the former than the latter. The formation of the protuberances at the step fronts is primarily associated with the uneven growth rates. The hollow cavities also elongate along the a direction, which demonstrates that the formation of them is also restricted by the crystal structure. Cracks are supposed to occur during harvesting, handling, or temperature stress afterwards. Growth of the 3D hillocks in high density can probably cause large stress and induce structure mismatch and serious cracks at the later stage.