Figure 3: In situ STM images of (A) cystamine and 2-PySH and (B) PDPH monolayers on Au(111) in 0.05 M HClO4. The potentials of the sample and tip were 0.9 V and 0.35 V vs. RHE, respectively. The tunneling current was 1 nA. (A) and (B) Image area: 200 nm × 200 nm.