NANOSTRUCTURED MATERIALS CHARACTERIZATION BY X-RAY DIFFRACTION

I. Dragomir – Cernatescu PANalytical Inc., 12 Michigan Drive, Natick, MA 01760, USA

e-mail: iuliana.cernatescu@panalytical.com

In nanotechnology, knowledge of the structure, micro/nano-structure and composition of the materials studied is a key requirement for understanding materials properties at a small distance. Understanding the preferred orientation gives insight in the growth, deposition or synthesis of the materials and in the materials properties.

Since the dimensions of X-ray wavelengths are in the same order as the sizes of nano-structures, X-ray diffraction is an important tool for the nano-scientist. X-ray diffractograms hold a wealth of structural information of the nano-materials. The micro/nano-structure of materials is given by fundamental features, such as: (i) the crystallite size, (ii) size distribution, (iii) the defect structure/distribution, (iv) texture, (v) micro and macro strain, etc. The two principal tools for describing the microstructure of nano-structured materials are electron and x-ray probes. The images of the TEM and electron diffraction provide information about the primary nano-structure in a very small region. X-ray diffraction provides complimentary information about the nano-structure by showing the average coherence length as a function of direction. The X-ray diffraction results are averaged over a large volume giving a overall view of the nano-structure. This paper will review the applications of X-ray diffraction Laboratory techniques for determining the nano-structure features of nano-materials. Examples of X-ray diffraction studies of nano-powders, nano-wires, nano-films samples will be presented.