Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 35: Spin controlled transport II

HL 35.6: Vortrag

Mittwoch, 27. Februar 2008, 15:30–15:45, ER 164

Observation of Spin Pair Generation with Pulsed Electrically Detected Magnetic Resonance — •Jan Behrends¹, Christoph Boehme^1,2, Manfred Schmidt¹, and Klaus Lips¹ — ¹Abt. Silizium-Photovoltaik, Hahn-Meitner-Institut Berlin, Berlin, Germany — ²Department of Physics, University of Utah, Salt Lake City, UT, USA

Due to its high sensitivity, pulsed electrically detected magnetic resonance (pEDMR) has proven to be an effective method to study paramagnetic defects in semiconductor devices. PEDMR measures changes in the (photo-) conductivity resulting from a spin-resonant alteration of charge carrier transport or recombination rates. The annihilation (recombination, dissociation) dynamics of spin pairs that form during the capture of charge carriers at localised defects have previously been studied in various materials and device structures. In contrast, the creation dynamics of spin pairs has not been investigated with pEDMR since it hardly influences the dynamic parameters measured. We demonstrate in this study a novel pEDMR rotary echo pulse sequence that allows such a quantitative analysis of spin pair generation. This procedure can be applied in principle to all materials and devices that are suitable for pEDMR measurements. The experiments presented here use this new approach for the investigation of the generation of electron spin pairs in amorphous silicon conduction band tail states in the emitters of crystalline silicon/ amorphous silicon heterostructure solar cells. The results will be discussed with regard to findings from previous pEDMR studies on hopping transport in similar devices.