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arXiv · 1302.4675

Optical spin orientation and depolarization in Ge

C. Rinaldi·M. Cantoni·R. Bertacco
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Abstract

Optical spin orientation and depolarization phenomena in semiconductors are of overwhelming importance for the development of spin-optoelectronics. In this paper we employ Ge-based spin-photodiodes to investigate the room temperature spectral dependence of optical spin orientation in Germanium, in the range 400-1550 nm, and the photo-carrier spin relaxation phenomena. Apart from the maximum in the spin polarization of photo-carriers for photon energy resonant with the direct gap (1550 nm), we experimentally demonstrate the presence of a second sizable peak at 530 nm due to photo-generation far away from the center of the Brillouin zone, within the L valleys. Furthermore, our data indicate that the equivalent the spin lifetime of holes in Ge is in the order of 5-10 ps, meaning that the spin diffusion length for holes at room temperature is larger than expected, in the order of 150-220 nm.

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C. Rinaldi, M. Cantoni, R. Bertacco. 2013-02-19. Optical spin orientation and depolarization in Ge. https://doi.org/10.1103/physrevb.90.161304

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