Silicon Nanowires. What is a Nanowire?.
Nanowires are experimental and are not available in commercial or industrial applications. The conductivity and tiny size make them ideal for future computer processors and connectors.
15um Silicon Nanowires (SiNW) grown on Si wafer with gold thin film
catalyst @ 550°C from Silane (SiH4) precursor gas.
Atomic configuration of a silicon wire created through etching of crystalline silicon. The wire is 3 nanometers long and one nanometer wide, attached to aluminum electrodes. The aluminum atoms are depicted as large blue balls; the silicon atoms as yellow balls, and the passivating hydrogen atoms as small blue balls.
Electronic density of states near the Fermi level for undoped (left) and doped (right) silicon nanowires created through an assembly of silicon clusters, and connected to aluminum electrodes. In both cases, the density of states iso-surfaces (depicted in red) is superimposed on the atomic structure of the nanowire. Note the aluminum doping atoms inside each of the silicon clusters shown on the right. The electronic density of states extends through the entire doped nanowire, bridging the two connected aluminum electrodes, resulting in a low threshold bias voltage for the current flow through the doped nanowire. On the other hand, for the undoped nanowire (left), the density of states penetrates only a short distance into the silicon, and a relatively large bias voltage is required for current flow. Aluminum atoms are shown as large blue balls; silicon atoms as yellow balls and passivating hydrogen atoms as small bluballs.
The orientation of the wire axis and the surface have a great effect on the electronic properties of SiNWs.
Figure 1. Diagram of the silicon nanowire solar cell. Each individual nanowire is a tiny p-n junction. The darker outer shell is n-type silicon. The lighter inner core is p-type silicon.