Quantum Confinement in Meteoritic Nanodiamonds
T. Berg1,2, E. Marosits2, J. Maul1, P. Nagel3, U. Ott2, F. Schertz1, S. Schuppler3, Ch. Sudek2 and G. Schönhense1
1Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
Meteoritic nanodiamonds were the first presolar material that was identified in 1987 . The sizes of these particles are not random, but follow a lognormal size distribution with a median diameter of only 2.6 nm . We analyzed the carbon K-edge region of these size distributed meteoritic nanodiamonds extracted from the Murchison meteorite and of mm-sized artificial CVD diamonds by near edge X-ray absorption fine structure (NEXAFS) measurements with high energy resolution. The results proved to be of interest for nanotechnological applications concerning quantum mechanical properties of nanoparticles . The C 1s core exciton peak and the C 1s absorption edge is blue shifted, asymmetric and broadened in the case of the nanodiamonds compared to the bulk like CVD sample. We performed a detailed quantitative analysis of this modified peak shape based on quantum confinement effects in nanoparticles. These effects play an important role in the design of a multiplicity of devices like diode lasers , biological sensors  and solid state quantum computers . Further, a C 1s core exciton peak was observed for the first time in meteoritic nanodiamonds.
Fig. 1: Comparison of the carbon K-edge NEXAFS of artificial bulk-like CVD diamonds (a) and of size-distributed meteoritic nanodiamonds (b). The inset in (a) describes the superposition of the X-ray absorption edge with the Lorentzian-shaped exciton peak. The inset in (b) shows a transmission electron microscopic (TEM) image of a single meteoritic nanodiamond.
A detailled quantitative analysis of the performed NEXAFS measurements in respect to quantum confinement effects was publised in:
Quantum confinement observed in the X-ray absorption spectrum of size distributed meteoritic nanodiamonds extracted from the Murchison meteorite
Quantum confinement observed in the X-ray absorption spectrum of size distributed meteoritic nanodiamonds
 "Interstellar diamonds in meteorites", R.S. Lewis et al., Nature 326(1987)160-162.
|Last update: Wednesday, 02-Nov-2011 17:09:11 CET D. Panzer||Impressum|