AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Tuesday Sessions
       Session NS+EM-TuM

Paper NS+EM-TuM10
Low Temperature Scanning Tunneling Spectroscopy on Cleaved InAs Quantum Dots

Tuesday, November 1, 2005, 11:20 am, Room 210

Session: Nanoscale Electronic Devices & Detection
Presenter: A. Urbieta, IEMN, (CNRS, UMR 8520) France
Authors: A. Urbieta, IEMN, (CNRS, UMR 8520) France
B. Grandidier, IEMN, (CNRS, UMR 8520) France
J.P. Nys, IEMN, (CNRS, UMR 8520) France
D. Deresmes, IEMN, (CNRS, UMR 8520) France
D. Stiévenard, IEMN, (CNRS, UMR 8520) France
Y.M. Niquet, CEA/DRFMC/SP2M, France
Correspondent: Click to Email
InAs quantum dots (QDs) have attracted increasing attention in recent years due to their application in optoelectronic devices such as infrared solid state lasers.@footnote 1@ Therefore, a complete knowledge of the electronic structure of the mentioned dots is essential in order to improve device design, performance and reliability. QDs are zero-dimensional structures also known as artificial atoms since they exhibit three dimensional confinement leading to atomic-like electronic states. Much effort has been devoted in the last decade to determine the characteristics of these states from both theoretical and experimental viewpoints. The spectroscopic mode of scanning tunneling microscope (STM) at cryogenic temperatures is a powerful tool to study low dimesional structures, since it enables a detailed characterization of their local electronic properties with high resolution. Actually, electron states in free-standing InAs QDs grown on n-type GaAs have been successfully investigated using this technique.@footnote 2@ However, a complete characterization of QD-related hole states is still lacking. In this work, scanning tunneling spectroscopy at low temperatures has been used to investigate the electronic structure of cleaved InAs quantum dots growth on p-type (001) GaAs. Several peaks related to energy levels of electrons and holes confined in the dots have been observed. The experimental results are compared with tight-binding calculations of the electronic structure of similar quantum dots, which allow us to determine both the ground state and first excited states of electrons and holes. Wave function mappings have been also carried out in order to assess the symmetry of the QDs states. @FootnoteText@ @footnote 1@ Y. Qiu, P. Gogna, S. Forouhar, A. Stintz and L. F. Lester, Appl. Phys. Lett. 79, 3570 (2001).@footnote 2@ T. Maltezopoulus, A. Bolz, C. Meyer, C. Heyn. W. Hansen, M. Morgenstern and R. Wiesendanger, Phys. Rev. Lett. 91, 196804 (2003).