The selective removal of metallic carbon nanotubes from As-grown arrays on insulating substrates

We present a method of selectively removing metallic single-walled carbon nanotubes (SWCNTs) from as-grown arrays on quartz substrates. The process utilizes an external silicon piece as a temporary global top gate to increase the resistance of the semiconducting SWCNTs while current is passed through the metallic SWCNTs, causing electrical breakdown through joule heating. The resulting SWCNT field-effect transistors (FETs) consistently produce on/off current ratios greater than 1000. Additionally, we find that the high frequency parasitic losses between 1 GHz and 6 GHz on the completed SWCNT FETs are significantly lower than on comparable SWCNT FETs fabricated on silicon substrates.