Robert L. Wallace Professor of Applied Physics of Harvard's School of Engineering and Applied Sciences (SEAS) along with his student and Prof. Carsten Ronning of the University of Jena have developed a new technique for fabricating nanowire photonic and electronic integrated circuits that may be suitable for high-volume commercial production in future. Assembling nanowires in large quantities into functional circuits have posed a major challenge for long time. By incorporating spin-on glass technology used in silicon integrated circuits manufacturing and photolithography and transferring a circuit pattern onto a substrate with light, the team has demonstrated a reproducible, high-volume and low-cost fabrication method for integrating nanowire devices directly onto silicon. Fabrication technique has been made independent of the geometrical arrangement of the nanowires on the substrate and controlled placement and alignment of nanowires over large areas has been possible. In this method a nanowire is placed between the highly conductive substrate, which functions as a common bottom contact, and a top metallic contact, using spin-on glass as a spacer layer to prevent the metal contact from shorting to the substrate. As a result current can be uniformly injected along the length of the nanowires. These devices can then function as light-emitting diodes, with the color of light determined by the type of semiconductor nanowire used. The team has already fabricated hundreds of nanoscale ultraviolet light-emitting diodes by using zinc oxide nanowires on a silicon wafer. More broadly, because nanowires can be made of materials commonly used in electronics and photonics, they hold great promise for integrating efficient light emitters, new class of integrated circuits and from ultraviolet to infrared, large arrays of ultra-small nanoscale lasers that could be designed as high-density optical interconnects or be used for on-chip chemical sensing with silicon technology. The team plans to further refine their novel method with an aim towards electrically contacting nanowires over entire wafers.