Direct Imaging of InGaAs Quantum Dot States by Scanning Tunneling Spectroscopy
A combination of scanning tunneling microscopy and spectroscopy has been employed to directly image the charge density of the confined electronic states of In0.5Ga0.5As quantum dots produced by epitaxial Stranski-Krastinov growth. Room temperature measurements have been made of intact, uncapped quantum dots, in a planar geometry. The tunneling current images have been compared with calculated tunneling current profiles and the observed tunneling current contrast has been associated with the localized quantum dot states and the delocalized wetting layer states.
KeywordsScanning Tunneling Microscopy Tunneling Current Occupied State Unoccupied State Scan Tunneling Spectroscopy
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- 1.R. M. Feenstra, J. A. Stroscio, J. Terso., A. P. Fein, Phys. Rev. Lett. 58, 1192 (1987); C. Joachim, J. K. Gimzewski, R. Schlittler, and C. Chavvy, Phys. Rev. Lett. 74, 2102 (1995); P. G. Collins, J. C. Grossman, M. Cote, M. Ishigami, C. Piskoti, S. G. Louie, M. L. Cohen, and A. Zettl, Phys. Rev. Lett. 82, 2102 (2000).CrossRefGoogle Scholar
- 6.J. Shumway, A. J. Williamson, A. Zunger, A. Passaseo, M. DeGiorgi, R. Cingolani, M. Catalano, and P. Crozier, Phys. Rev. B., submitted.Google Scholar
- 7.M. De Giorgi, A. Passaseo, R. Cingolani, A. Taurino, and M. Catalano, Phys. Rev. B. (submitted).Google Scholar
- 8.C. B. Duke, Tunneling in Solids, (New York, London: Academic).Google Scholar
- 14.A. Vasanelli, M. De Giorgi, R. Ferreira, R. Cingolani, and G. Bastard, Physica E, in press.Google Scholar
- 15.R. Wiesendanger, Scanning Probe Microsocpy and Spectroscopy, Cambridge University Press (1998).Google Scholar