Fundamentals of Hierarchical Nanostructures - Hierarchical Nanostructures for Energy Devices - page 13

d n 3 r 4 n g | 7

. Figure 2.2 (a) This false-color image of a suspended platform shows all

electrical connections. The central green area is the Si nanowire array,
which is not resolved at this magnification. The four-lead yellow
electrodes are used for thermometry to quantify the temperature differ-
ence across the nanowire array. The thermal gradient is established
with either of the two Joule heaters (the right-hand heater is colored red).
The yellow and blue electrodes are combined to carry out four-point
electrical conductivity measurements on the nanowires. The grey region
underlying the nanowires and the electrodes is the 150-nm-thick SiO 2
insulator that is sandwiched between the top Si(100) single-crystal
film from which the nanowires are fabricated, and the underlying Si
wafer. The underlying Si wafer has been etched back to suspend the
measurement platform, placing the background of this image out of
focus. (b) Low-resolution micrograph of the suspended platform. The
electrical connections radiate outwards and support the device. (c) High-
resolution image of an array of 20-nm-wide Si nanowires with a Pt
electrode.
Reproduced with permission from ref. 48. Nature Publishing Group.