Ultra-thin silicon nitride barrier implementation for Si nano-crystals embedded in amorphous silicon carbide matrix with hybrid superlattice structure
Centre of Excellence for Advanced Silicon Photovoltaics and Photonics, University of New South Wales Sydney 2052, Australia
Accepted: 9 August 2011
A hybrid superlattice structure consisting of 30 periods of alternating amorphous Si0.7C0.3 (5 nm) layers and ultra-thin Si3N4 barrier layers (0.2–2.0 nm) has been synthesised by magnetron sputtering, with subsequent annealing by a rapid thermal annealing (RTA) process. Si nano-crystals behave well confined within individual layers when the Si3N4 layer thickness is over 0.8 nm, due to the Si very low diffusion coefficient in Si3N4 matrix. Hopping is regarded as the dominant carrier transportation mechanism in the film based on fitting the temperature-dependent I-V measurements results. In conclusion an optimum Si3N4 barrier layer thickness of approximately 0.8 nm may be appropriate as a candidate material for photovoltaic application.
PACS: 73.63.Kv – Quantum dots
© EPLA, 2011