New Method Grows Nanowires At Record Pace

A new gas-phase synthesis technique grows semiconductor nanowires on the fly at a rate of 1 µm per second—20 to 1,000 times faster than traditional methods (Nature, DOI: 10.1038/nature11652). The approach could enable low-cost industrial production of next-generation solar cells and batteries. To achieve the improved growth rate, researchers led by Lars Samuelson of Sweden’s Lund University begin with gold aerosol nanoparticles, which they heat and pass into a gas reactor tube. These gold seed particles combine with gallium from (CH₃)₃Ga and arsenic from AsH₃ to form tiny GaAs wires as they flow through the tube. Changing the size of the gold particles, the tube temperature, and the reaction time affects the quality and dimensions of the nanowires produced by this method, called aerotaxy. The limitation of traditional gas-phase epitaxy methods is that they grow nanowires on substrates in batches, rather than continuously, says Brian A. Korgel, a chemical engineer at the University of Texas, Austin. This new approach, Korgel adds, “is a big step toward future nanowire applications that will require large amounts of material.” The Swedish firms Sol Voltaics and QuNano have both filed patents related to the technique.