Time domain measurement of spin-dependent recombination - A novel defect spectroscopy method

A new defect characterization method is suggested which we call Time Domain Measurement of Spin-Dependent Recombination (TSR). Time resolved spin-dependent recombination rate changes in a semiconductor that is exposed to a strong magnetic field are measured, These rate changes are triggered by a spin resonant excitation of recombination centers and charge carriers through short and intensive microwave pulses. The coherence of the charge carrier-recombination center pair ensemble is already destroyed during the pulse by Fast recombination processes of the recombining pairs. After the pulse, a slow relaxation of the recombination rate into its steady state takes place which is caused by the dissociation of the recombination partners. Unlike Electrically Detected Magnetic Resonance (EDMR) which can only detect and quantify distinct recombination centers, TSR opens access to a variety of qualitative and quantitative information about electronically active defects due to the dependence of the signal transient on the various parameters. Particularly because of the possibility to measure recombination probabilities of distinct recombination paths directly, TSR could be a promising new approach to defect spectroscopy. The Feasibility of TSR is demonstrated with the dangling bond recombination path of microcrystalline silicon. (C) 2002 Elsevier Science B.V. All rights reserved.