Experimental Observation of Self-Organized Nanostructures in Layered Crystals

Abstract

Experimental evidence of nanostructures formation in layered crystals is discussed. Arrays of pyramid-like nanostructures formed in cadmium iodide crystals obtained either by vapor deposition or by using directional Bridgman-Stockbarger growth technique are directly observed using atomic force microscopy imaging and have influence on the optical spectra of the material. Nanostructured materials assembled from submicron-sized building blocks have a great potential for improving the performance of various electronic devices. Although modern nano-engineering allows manipulating the structure even at the atomic scale, there are also many self-organized nanosystems in nature (Rousset and Ortega, J Phys Condens Matter 18:null, 2006). Below, an example of such self-organized nanostructures will be addressed. Layered crystals exhibit specific properties due to their structure: atoms arrange in layers with ionic-covalent bonding, which are held together by relatively weak van der Waals forces. Specific defects, in particular, screw dislocations and related growth helices arising during crystal growth process can serve as nucleation centers for the formation of nanostructures in these materials.