Abstract
Molecular ordering of benzeneselenol (BSe) self-assembled monolayers (SAMs) on Au(1
1
1) substrates have been investigated by scanning tunnelling microscopy (STM)
[1]. After short immersion time (10
min), elevated islands with height of 2.4
Å were found to cover the entire gold surface. On and among the islands, the STM results exhibited the formation of a highly ordered phase (α-phase) by BSe species. In the present study, a novel method is presented to completely eradicate the elevated gold-islands. The method depends on a repetitive STM scanning over the same part of the SAM at restricted tunnelling conditions. After almost 6
h of successive scanning, the surface becomes clean and free of the elevated islands. Moreover, this method was found to induce phase transformation into β-phase. The size of the ordered domains of the β-phase was found to exceed five times that of α-phase. Such a long-range ordering of the β-phase at room temperature has not been previously observed for any system on Au(1
1
1). After detailed analyses, the β-phase was found to have a 33.5% of lower packing density than that of α-phase.