Fig. 4

Morphological control: the shape, the size and the layers. a, b STM images acquired on Au(111) surface after the deposition of a premixed TCB solution containing 25 µM (rac)-Au₃₈ and 25 µM (P)-1. a I_set = 100 pA, V_bias = –1 mV; b I_set = 100 pA, V_bias = −900 mV. c STM images showing the islands before and after the removal, by the STM tip, of adsorbed species. d Contrast STM image (2.3 × 4.6 nm²) and structural model of an array of (P)-1 at the step of a triangular island. e–h Histograms of the size of gold islands at various (P)-1 concentrations, from 0 µM (e), 10 µM (f), 25 µM (g) to 50 µM (h), while the concentration of (rac)-Au₃₈ is kept constant at 25 µM. The median sizes are indicated in blue. i Average island density and area versus the concentration of helicene in solution. The concentration of (rac)-Au₃₈ is 25 µM. The error bars were calculated as a s.d. of at least six images. j 3D mound formation in a mixture of 25 µM (P)-1 and 50 µM (rac)-Au₃₈. I_set = 140 pA, V_bias = –800 mV. The blue, yellow, red, and white colors in the inset outline four different layers. Scale bars: a, 100 nm; b, 10 nm; j, 50 nm