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HL: Halbleiterphysik
HL 44: Poster II
HL 44.23: Poster
Donnerstag, 11. März 2004, 16:30–19:00, Poster A
Field-dependence in the steady-state photocarrier grating technique: application to microcrystalline silicon — •Rudolf Brüggemann1 and Rashad I. Badran2 — 1Instut für Physik, Carl von Ossietzky Universität Oldenburg — 2Physics Department, The Hashemite University, Zarqa, Jordan
The steady-state photocarrier grating (SSPG) technique has become a standard tool for the characterisation of the minority carrier properties in amorphous and microcrystalline silicon. In the standard application the photocurrent response under the presence of spatially modulated photogeneration is measured at low electric fields. Here, we exploit the electric-field variation experimentally for microcrystalline silicon samples. The experimental results show a variation in the influence that the electric field imposes on the excess charge carriers, depending on the individual sample. For poor-quality samples there is hardly any influence in the measured SSPG parameter. In contrast, samples with high diffusion lengths show a large variation in the SSPG parameters. Analysis of our data with the theory by Abel et al. (1995) shows good correlation between experimental and theoretical values for a wide range of electric field, in particular in the transition region between diffusion dominated and drift-dominated transport.