Hamburg 2001 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

SYOF: Organische Festkörper

SYOF 5: Poster Session

SYOF 5.15: Poster

Dienstag, 27. März 2001, 17:00–19:00, Aula S3

An exactly solvable inverse problem: Calculation of the energy density of states in a disordered solid from its charge carrier density profile — •Jörg Stephan¹, Alfred Liemant², Fred Albrecht¹, and Ludwig Brehmer¹ — ¹Institut für Physik, Physik kondensierter Materie, Universität Potsdam, PSF 601553, D-14415 Potsdam — ²Weierstrass-Institut für Angewandte Analysis und Stochastik, Mohrenstr. 39, D-10177 Berlin

The density of states (DOS) of a disordered organic material can in principle be determined by measuring the charge carrier density of a suitably prepared sample with known thickness. A suitable experiment would involve introducing a well-defined amount of charges into the material, which is then sandwiched in a capacitor without making electrical contact between electrodes and sample. A stationary equilibrium distribution of charges will set up, characterised by a vanishing net current of drift and diffusion currents at each position within the sample. >From this equillibrium charge carrier profile the spatially independent energetic DOS can be deduced. We explain in detail the mathematical procedure that leads to the determination of the DOS and discuss the limitations of this method with respect to the amount of charges in the sample, the external field dependence and the influence of the temperature.