Properties of nitrogen/silicon doped vertically oriented graphene produced by ICP CVD Roll-to-roll technology

Abstract

Simultaneous mass production of high quality vertically oriented graphene nanostructures and doping them by using an inductively coupled plasma chemical vapor deposition (ICP CVD) is a technological problem because little is understood about their growth mechanism over enlarged surfaces. We introduce a new method that combines the ICP CVD with roll-to-roll technology to enable the in-situ preparation of vertically oriented graphene by using propane as a precursor gas and nitrogen or silicon as dopants. This new technology enables preparation of vertically oriented graphene with distinct morphology and composition on a moving copper foil substrate at a lower cost. The technological parameters such as deposition time (1-30 min), gas partial pressure, composition of the gas mixture (propane, argon, nitrogen or silane), heating treatment (1-60 min) and temperature (350-500 ° C) were varied to reveal the nanostructure growth, the evolution of its morphology and heteroatom's intercalation by nitrogen or silicon. Unique nanostructures were examined by FE-SEM microscopy, Raman spectroscopy and energy dispersive X-Ray scattering techniques. The undoped and nitrogen- or silicon-doped nanostructures can be prepared with the full area coverage of the copper substrate on industrially manufactured surface defects. Longer deposition time (30 min, 450 ° C) causes carbon amorphization and an increased fraction of sp3 -hybridized carbon, leading to enlargement of vertically oriented carbonaceous nanostructures and growth of pillars.