Silicon offers a compelling platform for developing hybrid architectures that exploit novel functionalities. Heteroepitaxial growth of Ge on Si is a prominent approach to tailor material properties to achieve this goal. However, designing Ge-based heterostructures, which fulfill ever-demanding photonic and electronic applications, demands crucial control over the unavoidable non-radiative recombinations occurring at free surfaces and growth defects like dislocations. Yet the mitigation over such parasitic optical activity remains an open issue. Here we tackle this problem and demonstrate a more than 2 orders of magnitude photoluminescence (PL) enhancement achieved via confinement of threading dislocations and carefully controlled surface passivation of micron-scale Ge on Si crystals. By spectrally resolving interband and dislocation-related PL, we underpin the role played by dislocations in limiting the radiative emission, and we identify effective solutions based upon bandgap engineering to further boosting light emission efficiency. Noticeably, by combining steady state and time-resolved PL we disentangle non-radiative channels due to free surfaces and dislocations, eventually shining light on their relative impact at various temperature regimes. These findings have the potential of being beneficial for numerous applications of Ge-based heterostructures, in particular for moving forward their exploitation within the fast-growing field of Si-photonics.

Pezzoli, F., Giorgioni, A., Gallacher, K., Isa, F., Biagioni, P., Millar, R., et al. (2016). Dislocation recombination and surface passivation of Ge micro-crystals on Si. Intervento presentato a: EMRS 2016 Spring Meeting, Symposium K: Group IV Semiconductors Materials Research: Growth, Characterization and Applications to Electronics and Spintronics, Lille, France.

Dislocation recombination and surface passivation of Ge micro-crystals on Si

PEZZOLI, FABIO
Primo
;
GIORGIONI, ANNA
Secondo
;
GATTI, ELEONORA;GRILLI, EMANUELE ENRICO;MIGLIO, LEONIDA
Ultimo
2016

Abstract

Silicon offers a compelling platform for developing hybrid architectures that exploit novel functionalities. Heteroepitaxial growth of Ge on Si is a prominent approach to tailor material properties to achieve this goal. However, designing Ge-based heterostructures, which fulfill ever-demanding photonic and electronic applications, demands crucial control over the unavoidable non-radiative recombinations occurring at free surfaces and growth defects like dislocations. Yet the mitigation over such parasitic optical activity remains an open issue. Here we tackle this problem and demonstrate a more than 2 orders of magnitude photoluminescence (PL) enhancement achieved via confinement of threading dislocations and carefully controlled surface passivation of micron-scale Ge on Si crystals. By spectrally resolving interband and dislocation-related PL, we underpin the role played by dislocations in limiting the radiative emission, and we identify effective solutions based upon bandgap engineering to further boosting light emission efficiency. Noticeably, by combining steady state and time-resolved PL we disentangle non-radiative channels due to free surfaces and dislocations, eventually shining light on their relative impact at various temperature regimes. These findings have the potential of being beneficial for numerous applications of Ge-based heterostructures, in particular for moving forward their exploitation within the fast-growing field of Si-photonics.
Si
abstract + slide
Scientifica
Germanium, silicon, patterning, carrier lifetime, photoluminescence, dislocations, surface passivation
English
EMRS 2016 Spring Meeting, Symposium K: Group IV Semiconductors Materials Research: Growth, Characterization and Applications to Electronics and Spintronics
Pezzoli, F., Giorgioni, A., Gallacher, K., Isa, F., Biagioni, P., Millar, R., et al. (2016). Dislocation recombination and surface passivation of Ge micro-crystals on Si. Intervento presentato a: EMRS 2016 Spring Meeting, Symposium K: Group IV Semiconductors Materials Research: Growth, Characterization and Applications to Electronics and Spintronics, Lille, France.
Pezzoli, F; Giorgioni, A; Gallacher, K; Isa, F; Biagioni, P; Millar, R; Gatti, E; Grilli, E; Isella, G; Paul, D; Miglio, L
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/128891
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