Regensburg 2007 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 12: Quantum dots and wires: Optical properties I
HL 12.5: Vortrag
Montag, 26. März 2007, 15:45–16:00, H17
Spin Injection into Single InGaAs Quantum Dots — Mohsen Ghali1, Tilmar Kümmell1, •Robert Arians1, Gerd Bacher1, Jan Wenisch2, Suddhasatta Mahapatra2, and Karl Brunner2 — 1Werkstoffe der Elektrotechnik, Universität Duisburg-Essen, Bismarckstraße 81, 47057 Duisburg — 2Experimentelle Physik III, Universität Würzburg, Am Hubland, 97074 Würzburg
Single quantum dots are highly interesting candidates for potential spin-based devices. In order to implement a technology that utilizes the spin as an information carrier, one needs to initialize, store and detect a single spin. While diluted magnetic semiconductors like ZnMnSe have been proven to be an efficient source of spin polarized carriers, InAs-based quantum dots provide high spin stability with relaxation times up to milliseconds.
Using magneto-micro photoluminescence experiments, we found an efficient spin injection from a n-ZnMnSe layer into an InAs single quantum dot (SQD) in a p-i-n diode structure resulting in a circular polarization degree of up to 60% at B=5T. In contrast, no polarized light emission due to spin injection was obtained in an undoped reference structure. Furthermore, a pronounced dependence of the spin injection efficiency on the external bias is found resulting in a strong decrease of the SQD circular polarization degree when external biasing is applied in the forward direction. The experiments emphasize the impact of excess energy and current flow on the spin injection efficiency in a SQD.