Figure 1.

STM images of one monolayer of Chl a. (a) 214.5 × 214.5 nm, (c) 70 × 70 nm, (d) 35 × 35 nm, and the graphite surface (b) 4 × 4 nm. The monolayer is transferred at a surface pressure of 20 mN/m onto graphite. The imaging was in air, and the tunneling current and the bias voltage were set to 0.1 nA and −300 mV, respectively.