Figure 2.

Empty-state STM images of the densely packed molecular structures. (a) and (b): the closed layer PTCDA structure obtained when the molecules are adsorbed on a sample kept at elevated to 100 °C temperature; (c) 0.6 ML of PTCDA molecules adsorbed on the sample kept at 100 °C. All STM images were acquired with a 2 pA tunnelling current and a 2.0 V bias voltage. The figure has been adapted from [31].