Hanle effect and electron spin polarization in InAs/GaAs quantum dots up to room temperature
2012 (English)In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 23, no 13, 135705- p.Article in journal (Refereed) Published
Hanle effect in InAs/GaAs quantum dots (QDs) is studied under optical orientation as a function of temperature over the range of 150-300 K, with the aim to understand the physical mechanism responsible for the observed sharp increase of electron spin polarization with increasing temperature. The deduced spin lifetime Ts of positive trions in the QDs is found to be independent of temperature, and is also insensitive to excitation energy and density. It is argued that the measured Ts is mainly determined by the longitudinal spin flip time (T1) and the spin dephasing time (T2 *) of the studied QD ensemble, of which both are temperatureindependent over the studied temperature range and the latter makes a larger contribution. The observed sharply rising of the QD spin polarization degree with increasing temperature, on the other hand, is shown to be induced by an increase in spin injection efficiency from the barrier/wetting layer and also by a moderate increase in spin detection efficiency of the QD.
Place, publisher, year, edition, pages
IOP Publishing , 2012. Vol. 23, no 13, 135705- p.
National CategoryNatural Sciences Condensed Matter Physics
IdentifiersURN: urn:nbn:se:liu:diva-75096DOI: 10.1088/0957-4484/23/13/135705ISI: 000301663900015OAI: oai:DiVA.org:liu-75096DiVA: diva2:503748
funding agencies|Swedish Research Council| 621-2011-4254 |2012-02-162012-02-162013-10-02Bibliographically approved