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Materials 2013, 6(10), 4523-4531; doi:10.3390/ma6104523
Article

Room-Temperature Electron Spin Generation by Femtosecond Laser Pulses in Colloidal CdS Quantum Dots

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Received: 7 August 2013; in revised form: 16 September 2013 / Accepted: 8 October 2013 / Published: 15 October 2013
(This article belongs to the Special Issue Spintronics)
Download PDF [211 KB, uploaded 15 October 2013]
Abstract: We present an experimental investigation of optical spin orientation in colloidal CdS quantum dots (QDs) by a femtosecond laser pulse at room temperature. The spin carrier and its spin-generation process are clarified. Firstly, the observed spin signals of CdS QDs in time-resolved Faraday rotation measurements are shown to belong to electron carriers, by comparing the spin dephasing dynamics and Landé g factor between CdS QDs and bulk materials. Secondly, spin dynamics unaffected by the faster carrier recombination suggests that the spin-polarized electrons are not photoexcited but resident in the dots. Moreover, hole spins should dephase very fast compared with electron spins, otherwise the trion (two electrons with opposite spin orientations and one hole) recombination process will affect the resident electron spin signals. The electron spin is generated in a short time of which the excitation light is absorbed and the resident electron is excited to trion states, i.e., of pulse durations. Due to fast hole spin dephasing, trion recombination gives null spin signals, and the subsequent electron spin dynamics is controlled by its intrinsic mechanisms.
Keywords: electron spin; optical manipulation; pump-probe; quantum dots electron spin; optical manipulation; pump-probe; quantum dots
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Tong, H.; Feng, D.; Li, X.; Deng, L.; Leng, Y.; Jia, T.; Sun, Z. Room-Temperature Electron Spin Generation by Femtosecond Laser Pulses in Colloidal CdS Quantum Dots. Materials 2013, 6, 4523-4531.

AMA Style

Tong H, Feng D, Li X, Deng L, Leng Y, Jia T, Sun Z. Room-Temperature Electron Spin Generation by Femtosecond Laser Pulses in Colloidal CdS Quantum Dots. Materials. 2013; 6(10):4523-4531.

Chicago/Turabian Style

Tong, Haifang; Feng, Donghai; Li, Xiao; Deng, Li; Leng, Yuxin; Jia, Tianqing; Sun, Zhenrong. 2013. "Room-Temperature Electron Spin Generation by Femtosecond Laser Pulses in Colloidal CdS Quantum Dots." Materials 6, no. 10: 4523-4531.


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