AVS 52nd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP17
The Adsorption Structure of Histidine on Ge(100)

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Surface Science Poster Session
Presenter: S.J. Jung, Korea Advanced Institute of Science and Technology (KAIST), Korea
Authors: S.J. Jung, Korea Advanced Institute of Science and Technology (KAIST), Korea
S. Kim, Korea Advanced Institute of Science and Technology (KAIST), Korea
S. Hong, Sejong University, Korea
Correspondent: Click to Email
The adsorption of histidine molecule on the Ge(100)-2×1 surface was investigated using both scanning tunneling microscopy (STM) and the density functional calculation. Various adsorption features of histidine are founded to be formed under different conditions of temperatures and coverages. When histidine is exposed to a clean Ge(100) surface at 300 K, the histidine appears as round shaped bright protrusion in STM image, which is randomly distributed over the surface. After annealing the surface at 380 K, we found a short range ordering in molecular rows. When histidine is deposited onto Ge (100) at 380 K, histidine is found to form dumbbell shape protrusions that are located in either parallel or vertical direction to the dimer row. At the saturation coverage (Θ= 0.25 ML), however, the STM image show globally ordered array consisted of dumbbell shape features without regard to the direction of dimer row of the Ge (100) surface. Such global ordering implies that the interaction between histidine molecules is much more significant than the interaction between the molecules and the surface dimer. The ab initio calculation also suggests that the surface at saturation coverage has an additional stability, induced by the lateral interaction, compared to that at low coverage. Based on the STM results and ab initio calculation, we will present the adsorption structures, inter-molecular interaction and ordering of histidine molecules on the Ge(100) surface.