Nanowires grown on wafers
1 min read
Building on earlier work, researchers from NIST in the US have used conventional semiconductor manufacturing techniques to grow nanowires horizontally on the surface of a wafer.
In the process, small amounts of gold are deposited in precise locations on a sapphire wafer. In a high temperature process, the gold deposits bead up into nanodroplets that act as nucleation points for crystals of zinc oxide. A mismatch in the crystal structures of zinc oxide and sapphire induces the semiconductor to grow as a narrow nanowire in one particular direction across the wafer. Because the starting points and the growth direction are known, NIST says it is ‘relatively straightforward’ to add electrical contacts and other features through additional lithography steps.
As a proof of concept, NIST researchers have used this approach to create more than 600 nanowire based transistors in a single process. In this process, say the researchers, the nanowires typically grew in bunches of up to eight wires at a time, but they believe that finer control over the size of the initial gold deposits could make it possible to select the number of wires in each position.
The technique is likely to allow industrial scale production of nanowire based devices.
