We studied spin properties of Ge heterostructures by optical orientation and Hanle measurements. The circular polarization of the direct gap photoluminescence is shown to exceed the theoretical bulk limit, yielding about 37% and 85% for transitions with heavy and light holes, respectively. The energetic proximity of Γ and L valleys and ultrafast scattering of electrons from Γ to L states allowed us to resolve the spin dynamics of holes and to observe the polarization of electrons after scattering to L valleys. The spin relaxation analysis indicates that the spin lifetime of electrons exceeds 5 ns below 150 K, whereas it is in the 500 ps range for holes. © 2012 SPIE
Pezzoli, F., Bottegoni, F., Trivedi, D., Ciccacci, F., Giorgioni, A., Li, P., et al. (2012). Optical spin injection and spin lifetime in Ge heterostructures. In Proceedings SPIE 8461, Spintronics V, 84610P (October 1, 2012). S P I E - International Society for Optical Engineering [10.1117/12.929204].
Optical spin injection and spin lifetime in Ge heterostructures
PEZZOLI, FABIO
;GIORGIONI, ANNA;Cecchi, S;GRILLI, EMANUELE ENRICO;GUZZI, MARIO;
2012
Abstract
We studied spin properties of Ge heterostructures by optical orientation and Hanle measurements. The circular polarization of the direct gap photoluminescence is shown to exceed the theoretical bulk limit, yielding about 37% and 85% for transitions with heavy and light holes, respectively. The energetic proximity of Γ and L valleys and ultrafast scattering of electrons from Γ to L states allowed us to resolve the spin dynamics of holes and to observe the polarization of electrons after scattering to L valleys. The spin relaxation analysis indicates that the spin lifetime of electrons exceeds 5 ns below 150 K, whereas it is in the 500 ps range for holes. © 2012 SPIE
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