Properties of Nitrogen/Silicon Doped Vertically Oriented Graphene Produced by ICP CVD Roll-to-Roll Technology

Petr Rozel,Evgenij Khokhlov,Alexander Basaev,Vladimir Shiripov,Nikolay Kargin,Darya Radziuk,Vladimir Labunov,Iva Matolínová,Vladimír Matolín,Lubov Mikhnavets

doi:10.3390/coatings9010060

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.

Highlights

The importance of spatial alignment of one-dimensional carbonaceous nanomaterials to their applications such as field emitters, electromechanical actuators, gas sensors, and catalysts has been well recognized [1,2,3,4,5,6]
An inductively coupled plasma chemical vapor deposition (ICP CVD) system consisting of a vacuum chamber with a 22 cm diameter radio frequency (RF) inductive coil connected to a matching block (MB) was designed by IZOVAC Technologies Ltd. (Minsk, Belarus)
We examined the effects of the following technological parameters on the morphology and content of Vertically oriented graphene (VOG) coatings: (1) deposition time at isothermal

Summary

Introduction

The importance of spatial alignment of one-dimensional carbonaceous nanomaterials (nanotubes, nanowires, nanorods) to their applications such as field emitters, electromechanical actuators, gas sensors, and catalysts has been well recognized [1,2,3,4,5,6] These spatial alignment effects have been further extended to two-dimensional (2D) nanostructures, such as graphene. Higher electron conductivity and ion diffusivity, the cycling stability and larger surface area of VOG make it a competitive material for specific capacitance and its retention [13]. In Li-ion battery application, additional sites in VOG such as cavities, edges of the graphene basal planes, and those with hydrogen terminated groups act as hosts for charge carriers, thereby effectively increasing capacity compared to natural graphite or activated carbon [14,15]. For enhanced VOG performance in a specific surface area, its composition and the interlayer spacing should be well controlled during the preparation process

Methods

Results

Conclusion