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Langmuir 1999, 15, 3018-3020
Additions and Corrections Coverage-Dependent Phases and Phase Stability of Decanethiol on Au(111) G. E. Poirier Langmuir 1999, 15, 1167. Figures 1 and 4 were printed in the issue with insufficient contrast to properly support the points discussed in the paper. The Journal regrets that the detail of the original figures was not adequately reproduced in the printed issue. Images of higher fidelity and captions for Figures 1 and 4 follow. LA9902744 10.1021/la9902744 Published on Web 03/24/1999
Figure 1. Molecular-resolution constant-current STM topographs of phases of decanethiol on Au(111). Schematized molecular models are overlaid on topographs to show hypothetical registry. Molecules drawn in bold represent displacement out of the surface plane. The scale bar and crystallographic indicator in A also applies to parts B-E. (A) Au(111) exposed to 10-6 Torr of decanethiol for 240 s and imaged at 400 pA and 1.2 V sample bias. The surface region shows two commensurate domains of β-phase decanethiol separated by a region of R-phase lattice gas. (B) Au(111) exposed to 10-6 Torr of decanethiol for 380 s, stored in ultrahigh vacuum for 5 days, and imaged at 350 pA and 1.0 V sample bias. The left half of image is characteristic of the decay product of the χ phase, and the right half is characteristic of the β phase. The line segment in the right half shows lateral displacement of β-phase rows by influence of the Au reconstruction that underlies the monolayer at the region indicated by the crossed lines. (C) Au(111) exposed to 10-6 Torr decanethiol for 300 s and imaged at 400 pA and 1.2 V sample bias. Parallel line segments indicate antiphase boundaries. (D) Au(111) exposed to 10-6 Torr for 480 s and imaged at 150 pA and 1.2 V sample bias. The surface region shows coexistence of β, δ, and phases. Azimuthal orientation of the alkyl chains is retained across the β-δ phase boundary. Parallel line segments indicate antiphase boundaries. (E) The same surface preparation and tunneling conditions as those in D but with a different geometry of tip-apex atoms. We assume that the tip used in D highlights alkyl chain corrugation whereas the tip used in E highlights thiolate-bonding electrons.
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Figure 4. Constant-current STM topographs showing the evolution of the apparent surface structure after gas-phase exposure of Au(111) to ≈10-6 Torr decanethiol. The scale bar and crystallographic indicator in A applies also to B-F. (A) Au(111) exposed for 300 s shows striped molecular monolayer islands (β) coexisting with lattice gas (R). The dark feature in the upper right is a preexisting vacancy island surface defect. (B) Au(111) exposed for 420 s shows χ and β phases in coexistence. Black arrows indicate the β-χ phase boundary, white arrow indicate the paired antiphase boundary defect in the β-phase domain, black pointing fingers indicate the Au herringbone reconstruction residing beneath β-phase domains, and white pointing fingers indicate monatomic Au step edges, the contrast of which was artifically lowered. (C) Au(111) exposed for 480 s shows a surface dominated by χ-phase domains with residual sinuous β-phase domains. Pointing fingers indicate nascent, assembly-induced Au vacancy islands. (D) Au(111) exposed for 480 s shows δ and χ phases in coexistence. Black arrows indicate the χ-δ phase boundary, and white arrors indicate χ-phase defects. β-phase domains persist in the upper right. (E) Au(111) exposed for 510 s shows nucleation and growth of the fluid phase () at the δ-phase domain boundary network. (F) The same surface region and exposure as that in part E. The dense phase (φ) nucleates homogeneously in the -phase domains and grows laterally. Residual β- and -phase domains persist.
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Figure 4. Continued.
Additions and Corrections
