The nature of dangling bond recombination in μc-Si:H

Abstract Pulsed electrically detected magnetic resonance (EDMR) is used for the investigation of the dynamics of dangling bond (db) recombination in undoped microcrystalline silicon (μc-Si:H). Coherent microwave pulses in electron spin resonance with the paramagnetic db center (Lande factor g ≈2.005) stimulate Rabi oscillation that is detected by transient photoconductivity measurements. This allows experimental access to coherent spin motion effects on recombination revealing two different recombination mechanisms in μc-Si:H: (i) tunneling between shallow tails states and dbs and (ii) a recombination channel involving db centers which are strongly coupled to charge carriers that have almost identical g -factors. The latter is indicative of a process that involves the direct capture of electrons into charged, excited dangling bond states (db −∗ ) with energies close to the conduction band. This process is followed by spin-dependent readjustment into the charged ground state of the defect (db − ). Recombination is terminated by hole capture. Details of this recombination mechanism are discussed.