Regensburg 2004 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 12: Colloids and Nanoparticles II

CPP 12.6: Vortrag

Montag, 8. März 2004, 17:00–17:15, H 39

High-resolution photoemission study of CdS nanoparticles with narrow size distribution: preparation, different sulfur components, and beam damage effects — •Sanjeev Joshi¹, L. Weinhardt¹, C. Kumpf¹, S. K. Kulkarni², R. Fink³, C. Heske¹, and E. Umbach¹ — ¹Exp. Phys. II, Univ. Würzburg, 97074 Würzburg — ²Dept. Physics, Univ. Pune, Pune 411 007, India — ³Phys. Chem. II, Univ. Erlangen, 91058 Erlangen

We report on high resolution X-ray photoemission data of very small CdS nanoparticles of two different sizes, 1.4 nm and 2.7 nm diameter, respectively. A detailed analysis is performed to identify the sizes and their distribution and the various signal constituents. The signal is composed of five S components, which can be assigned to the S atoms of the particle in different environments. The peak assignment is done by comparing the experimental data with intensity estimates, considering the intensity attenuation and contributions of the various S atoms using three structural models. Furthermore, it is discussed how beam damage can be induced and how it is identified and controlled by recording very fast photoemission scans. A quantitative description based on successively collected spectra is developed. The influence of different thin film sample preparation methods on the photoemission signal is discussed as well.