Carrier multiplication in germanium nanocrystals

Saeed, Saba; de Weerd, Chris; Stallinga, Peter; Spoor, Frank C. M.; Houtepen, Arjan J.; Siebbeles, Laurens D. A.; Gregorkiewicz, Tom

http://hdl.handle.net/10400.1/11277

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Authors

Siebbeles, Laurens D. A.

Gregorkiewicz, Tom

Abstract(s)

Carrier multiplication is demonstrated in a solid-state dispersion of germanium nanocrystals in a silicon-dioxide matrix. This is performed by comparing ultrafast photo-induced absorption transients at different pump photon energies below and above the threshold energy for this process. The average germanium nanocrystal size is approximately 5-6 nm, as inferred from photoluminescence and Raman spectra. A carrier multiplication efficiency of approximately 190% is measured for photo-excitation at 2.8 times the optical bandgap of germanium nanocrystals, deduced from their photoluminescence spectra.

Keywords

Multiple exciton generation Silicon nanocrystals Auger recombination Solar-cells Quantum confinement Impact ionization Pbse nanorods Efficiency Films Photoluminescence