Berlin 2008 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 53: Optical properties
HL 53.10: Talk
Friday, February 29, 2008, 13:00–13:15, EW 201
The influence of size, shape, and targeted surface modification on the optical properties of small nanodiamonds — •Lasse Landt1, David Wolter1, Peter Schreiner2, Andrey Fokin2, Jeremy Dahl3, Robert Carlson3, Thomas Möller1, and Christoph Bostedt1 — 1Technische Universität Berlin, Germany — 2Justus-Liebig-Universität, Giessen, Germany — 3MolecularDiamond Technologies, USA
Diamondoids are a new exciting class of nano-carbon materials which can be considered the smallest possible cage-like subunits that can be excised from diamond lattice. They form a series of perfectly size- and shape-selectable, neutral nanodiamonds that grow only one crystal cage - or 4 carbon atoms - at a time. Therefore investigations on the size and shape dependence of the optical properties of these group IV nanocrystals have become feasible with atomic precision.
We have measured the optical absorption of diamondoids ranging from 0.5 to 1 nm in size, among them several isomeric structures. Our data show that the optical properties in this size regime are dominated by the crystal arrangement. In effect, it is found that the rearrangement of a single crystal cell outweighs a 30% size increase. We also present optical data on specifically surface modified diamondoids. Comparing the data sets of pristine and surface modified diamondoids represents a powerful tool to define the exact influence of selected surface modifications on the optical properties of such nanocrystals. All data were taken from neutral, high purity samples in the gas phase yielding unprecedented comparability to theoretical predictions.