A CMOS platform for the integration of heterogeneous arrays of carbon nanotubes and graphene chemiresistors

Abstract

We propose a “CMOS for nanoassembly” method to assemble carbon nanotubes and graphene on CMOS chip for gas sensing application. CNT's and graphene have been demonstrated as extremely sensitive chemiresistors for a wide range of analytes. The upper metal layers of the CMOS chip contain sixty electrodes of both planar and three-dimensional geometries. Each electrode is addressable through on chip circuitry. The electrodes are fully exposed by post-process dry etching. Chemiresistive assemblies of nanoscale single wall carbon nanotubes (SWNTs) and reduced graphene oxide (rGO) flakes are assembled onto the exposed electrodes by controlled dielectrophoresis (DEP), which is the motion of a polarizable particle in a dielectric medium. The utility of the platform is shown for gas sensing. To the best of our knowledge, this is the first time functional graphene and carbon nanotubes sensor elements have been integrated onto a single CMOS chip. Previous results indicate that the expansion of the chip to include other chemiresistive nanomaterials is entirely feasible.