Fig. 4: Electronic properties of Au₃₂-NC microcrystals.

a SEM micrograph of an individual microcrystal deposited on two horizontal Au electrodes on a Si/SiO_x device. The electrodes form a channel with length L = 2.8 µm. The width and height of the contacted microcrystal are W = 7.9 ± 0.4 µm and h = 120 nm. SEM and optical micrographs are merged. Scale bar: 5 µm. b Typical I–V curve of an individually probed microcrystal. Ohmic behavior is observed in the low voltage regime. c Distribution of conductivity σ of 54 individual microcrystals and 19 polycrystalline thin films. The conductivity of microcrystals exceeds that of polycrystalline films by ~2 orders of magnitude. d Temperature-dependent conductivity of Au₃₂-NC microcrystals with two individual measurements per temperature step. e FET transfer curve (blue) of a polycrystalline film of Au₃₂-NCs on an interdigitated electrode device with L = 2.5 µm, W = 1 cm, measured at V_SD = 10 V on a linear and logarithmic scale together with the negligible leak current (gray). Arrows indicate the corresponding y-axis. f FET transfer curve (red) of an individual microcrystal device with L = 1.5 µm, W = 10.4 ± 0.2 µm, measured at V_SD = 5 V, together with the negligible leak current (gray). The insets in (e) and (f) display optical micrographs of the two devices. Scale bars correspond to 500 and 10 µm, respectively.