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Study of charging dynamics and interaction energy measurements between electrons in different states in InAs self-assembled quantum dots

Grant number: 06/07052-2
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): April 01, 2007
Effective date (End): May 31, 2007
Field of knowledge:Physical Sciences and Mathematics - Physics
Principal Investigator:Gilberto Medeiros Ribeiro
Grantee:Marília Wellichan Mancini
Home Institution: Laboratório Nacional de Luz Síncrotron (LNLS). Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brasil). Campinas , SP, Brazil


The charging process of carriers into a quantum dot and also the level structure for both electrons and holes may be investigated through capacitance spectroscopy. Until now, it was not possible to map the binary electrostatic interactions between trapped electrons in different energy levels into a quantum dot, once with the technique based on the application of a constant voltage (quasi-static method) it is just possible to measure the net contribution of several interaction between all electronic states simultaneously occupied in the quantum dot.In this work, we intend to use a capacitance spectroscopy based technique, nevertheless using pulsed electric fields in spite of static fields, in order to evaluate the several binary interaction energy occurring between trapped electrons in InAs/GaAs self-assembled quantum dots. The interaction energy is basically the Coulomb blockade, and the exchange interaction, which occurs between two different states. We could also infer the spin-orbit interaction energies between, for instance, s and p states electrons. We also intend to measure the charging and discharging characteristic times of the each electronic state populated into the dots. The quantum dot samples used in the experiments will be produced by the MBE technique.