IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Wednesday Sessions
       Session TF-WeA

Paper TF-WeA5
Quantum Size Effects in 2D Pb Islands on Si(111)

Wednesday, October 31, 2001, 3:20 pm, Room 123

Session: Nucleation and Growth
Presenter: C.S. Chang, Academia Sinica, Taiwan, ROC
Authors: C.S. Chang, Academia Sinica, Taiwan, ROC
W.B. Su, Academia Sinica, Taiwan, ROC
S.H. Chang, National Tsing Hua University, Taiwan, ROC
W.B. Jian, Academia Sinica, Taiwan, ROC
L.J. Chen, National Tsing Hua University, Taiwan, ROC
T.T. Tsong, Academia Sinica, Taiwan, ROC
Correspondent: Click to Email
When the thickness of a metallic film approaches a few atomic layers, the de Broglie wavelength of its Fermi electrons becomes comparable to film thickness and quantum size effects (QSE) begin to appear. These effects, though originated from the electron confinement, can have a profound effect on various nano scale physical properties. For instance, Schulte@footnote 1@ earlier calculated the film thickness dependence of electron densities, potentials and work functions for free standing metal films and found oscillations in all these quantities. In addition, when the effect of discrete lattice is taken into account, the QSE can invoke the structural variations also. All these findings exemplify the unusual behavior of thin metal films varying with their thickness. However, clear experimental evidence directly relating quantized electronic states to interlayer relaxations of individual islands is still lacking. The first observation of the QSE for individual Pb islands grown on the Si(111) surface has been made by Altfeder et al.,@footnote 2@ and we have extended their work toward thinner films. Also in this study, individual 2D lead (Pb) islands of varying heights grown on the Si(111)7x7 surface at low temperature are investigated concurrently with real-space and local-probe scanning tunneling microscopy and spectroscopy. Quantum size effects, manifested as quantized electronic states and oscillatory relaxations in interlayer spacings are found perfectly correlated to each other. @FootnoteText@@footnote 1@F. K. Schulte, Surf. Sci. 55, 427 (1976). @footnote 2@I.B. Altfeder, K.A. Matveev, and D.M. Chen, Phys. Rev. Lett. 78, 2815 (1997).