AVS 56th International Symposium & Exhibition
    Surface Science Thursday Sessions
       Session SS1-ThA

Paper SS1-ThA2
Influence of Quantum Well States on the Formation of Surface Au/Pb Alloy in Pb/Si(111) Quantum Thin Films

Thursday, November 12, 2009, 2:20 pm, Room M

Session: Nucleation and Growth - Metals
Presenter: J.D. Kim, The University of Texas, Austin
Authors: J.D. Kim, The University of Texas, Austin
S.Y. Qin, The University of Texas, Austin
A. Khajetoorians, The University of Texas, Austin
W.G. Zhu, Oak Ridge National Laboratory
Z.Y. Zhang, Oak Ridge National Laboratory
C.K. Shih, The University of Texas, Austin
Correspondent: Click to Email
The thickness dependence of Au/Pb alloy formation on thin Pb quantum films is studied using in-situ low temperature STM/S. Sub-monolayer Au is deposited onto thin Pb films on Si(111) substrates. When Au deposition is carried out at low temperature (~100K), it is found that nano-islands with moire patterns form on top of Pb mesas. With annealing, these moire islands are transformed into three different types of Au/Pb surface alloys. Each type of alloy shows its unique electronic properties and can be clearly identified by STS. Interestingly, the formation of these alloys is directly related to quantum well states (QWS) of underlying Pb films. For thinner thicknesses of underlying Pb layers (below 12ML), it is also observed that the alloy formation probability has strong thickness preference.