Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 48: Poster 2

HL 48.29: Poster

Donnerstag, 26. März 2009, 15:00–17:30, P2

Manipulation of minority-majority mobility-lifetime-product behavior in microcrystalline silicon by field effect — •Oliver Neumann, Rudolf Brüggemann, and Gottfried H. Bauer — Institut für Physik, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg

Mobility-lifetime-products (µτ) of minority and majority carriers are a general criterion for the quality of semiconductors. The particular magnitudes can be separately analyzed by photoconduction experiments e.g. with the steady-state photocarrier grating technique (SSPG) [1] for the minority-carrier (µτ) products and traditional photoconductivity studies for the majority-carrier (µτ) products. The share between electrons and holes is used to be governed by the Fermi level which as well decides on minority and majority status.

We have performed SSPG (for minority (µτ)-products) as well as photoconductivity measurements on different hydrogenated microcrystalline silicon (µc-Si:H) samples with simultaneous application of an electric field in field-effect configuration for carrier depletion respectively accumulation. By this approach we proof experimentally with our SSPG- and photoconductivity-experiments to increase majority densities and decrease minority concentrations and we accordingly also shift the original majority behavior of electrons towards minority behavior. From our experiments we deduce the necessary electric field strengths for inversion in nominally undoped µc-Si:H.

[1] D. Ritter, E. Zeldov, K. Weiser, Appl. Phys. Lett. 49, 791 (1986).