Fig. 5: Bias polarity-dependent appearance of polyanthryl oligomer nano-islands on the Au(111) surface.
From: Long and isolated graphene nanoribbons by on-surface polymerization on Au(111)
a, b High-resolution STM topographs recorded after the 200 °C annealing step showing the distinct morphology of an oligomer nano-island at the positive bias of (a) + 2.0 V/10 pA and at the negative bias of (b) −2.0 V/10 pA. c Corresponding line profiles drawn across the oligomer island in (a) and (b) are presented with a blue and a red curve, respectively. The presence of two STM apparent heights reveals the bilayered configuration of polyanthryl oligomer islands at 200 °C annealing step. A reconstructed molecular model of two-layered oligomer structure is given in the inset. d–f A similar bias polarity dependent high-resolution STM topograph analysis carried out at the 250 °C annealing step resemble the 200 °C annealing step presented in (a–c), respectively. The presence of uniform and single STM apparent heights indicates the monolayered configuration of polyanthryl oligomer islands at the 250 °C annealing step. Scale bars are 5 nm in (a, b, d, e).
