Contacting single quantum dots with nano-electrodes [Elektronische Ressource] / vorgelegt von Conrad R. Wolf

Contacting single quantum dotswith nano-electrodesDissertationzur Erlangung des DoktorgradesDr. rer. nat.der Fakultät für Naturwissenschaftender Universität Ulmvorgelegt vonDipl.-Ing. (FH) Conrad R. Wolfaus Esslingen a. N.Juli 2010Amtierender Dekan: Prof. Dr. Axel Groß1. Gutachter: apl. Prof. Dr. Klaus Thonke2. Gutachter: Prof. Dr. Joachim Ankerhold3. Gutachter: Prof. Dr. Thomas IhnTag der mündlichen Prüfung: 30.11.2010iiiAbstractIn this thesis semiconductor quantum dots were contacted with nano-electrodes toyield single-electron devices. For this purpose different approaches for quantum dotpreparation and nano-electrode fabrication were investigated. The resulting deviceswere electrically characterized and their behavior was compared to theoretical models.For quantum dot preparation two approaches were taken. On the one hand, siliconquantumdotswerepreparedfromaSOIsubstratebymeansofaself-assembledcolloidaletch mask and reactive ion etching. On the other hand, CdSe/ZnS core/shell quantumdots were employed and deposited onto the electrodes with special linker molecules.To contact the quantum dots electrode pairs with a separation of only a few nanome-ters were necessary, which were obtained in three different ways. All methods werebased on electron beam lithography yielding electrode separations down to about10 nm. Electrode pairs with even smaller distance were fabricated with a controlledelectromigration process.