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HL: Halbleiterphysik

HL 24: Poster II

HL 24.64: Poster

Donnerstag, 29. März 2001, 10:30–19:00, Rang S\ 3

Diffusion photovoltage in poly-(p-phenylenevinylene — •volodimyr Duzhko¹, Thomas Dittrich¹, Boris Kamenev², Victor Yu. Timoshenko^1,2, and Wolfgang Bruetting³ — ¹Technische Universitaet Muenchen, Physik Department E16, D-85748 Garching, Germany — ²M. V. Lomonosov Moscow State University, Faculty of Physics, 119899 Moscow, Russia — ³Universitaet Bayreuth, Experimentalphysik II, D-95440 Bayreuth, Germany

Transient and spectral photovoltage phenomena are investigated in poly-(p-phenylenevinylene). The photovoltage transients are excited with short laser pulses and are retarded strongly in time. The retardation of the photovoltage transients depends on the sample thickness, laser intensity and bias illumination. The photovoltage signal is caused by separation of excess electrons and holes due to their concentration gradient and different diffusion coefficients (diffusion photovoltage). A numerical analysis yields a diffusion coefficient of excess holes on the order of 10-6 cm2/Vs, while the value for excess electrons is about 1-2 orders of magnitude lower, which is in good agreement with previous studies of charge carrier mobilities in PPV.