Silicon Nanoparticles Make Ever Smaller Electronics Possible

By Earl Boysen, Nancy C. Muir, Desiree Dudley, Christine Peterson

Silicon has been used in the manufacture of electronics for years. Just as it seemed that electronics couldn’t get any smaller, nanotechnology scientists have discovered ways to use silicon nanoparticles to extend the curve.

Besides being a snappy label for areas where computer technology thrives, silicon is an element whose atoms covalently bond together to form a semiconducting material. Wafers made of silicon crystal are used as the substrate on which computer chips are built, as well as being used in many types of solar cells. When silicon is bonded to other elements, it can also form useful materials such as glass.

Forming silicon nanoparticles or nanowires can change the optical and mechanical properties of the material and make it possible to build ever smaller computer chips year after year.

Silicon nanowires can be useful in building transistors, which are used in every integrated circuit. They would function as the channel of the transistor. The channel of a transistor is the smallest feature in an integrated circuit. As transistors used in integrated circuits continue to get smaller to fit more transistors on a computer chip, silicon nanowires may allow transistors to shrink further than current methods would allow.

Researchers have grown silicon nanowires on a stainless steel substrate. Batteries built with anodes using these silicon nanowires have up to ten times the power density of conventional lithium-ion batteries. Bulk silicon cracks due to both the swelling of silicon as it absorbs lithium ions when a battery is recharged and the contraction of silicon as the battery is discharged. Silicon nanowires eliminate cracking.

Researchers are developing silicon nanoparticles to be used for fluorescent imaging of diseased tissue in the body, such as cancer tumors. Because silicon is a semiconductor, silicon nanoparticles are part of the class of nanoparticles called quantum dots.