INVESTIGATION OF NANOSTRUCTURES BY SYNCHROTRON RADIATION

Václav Holý

Department of condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Czech Republic

Physical properties of nanostructures (quantum wires and dots, nano-rods, metallic nanostructures, among others) are substantially influenced by their morphology, lattice structure and lattice perfection. For the investigation of these structure parameters, x-ray small-angle scattering and x-ray diffraction are the methods of choice. Since the useful scattered signal is usually proportional to the volume or square of the volume of the objects, in the case of nanometer-sized objects the application of synchrotron radiation is inevitable.

In addition to a very high flux and brilliance of a synchrotron beam, which makes it possible to perform “standard” x-ray experiment on very small objects, other unique properties of synchrotron radiation are used for the study of nanostructures, such as a very high beam coherence, ideal polarization of the beam, and tunable photon energy. These properties enable us to measure x-ray scattering from a single nano-object, to carry out absorption spectroscopy studies in one nano-object (methods EXAFS, XANES and DAFS) and to determine the phase of the scattered radiation.

The talk will summarize basic experimental and theoretical approaches for synchrotron studies of nanostructures and will present several experimental examples, concerning mainly semiconductor quantum dots, quantum wires and nano-rods.