growth of carbon nanomaterials by chemical vapour deposition
TRANSCRIPT
Growth of Carbon Nanomaterials by
Chemical Vapour Deposition
1 Department of Electronic & Electrical Engineering, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom
G. D. T. Spratt1 & M. T. Cole1*
Aims
To synthesise carbon nanotubes (CNTs) using the method of chemical vapour deposition (CVD) and
investigate the effects of adjusting the growth environment to maximise the yield and quality. To use
photolithography techniques in order to produce the University of Bath logo in CNTs, to help understand
potential uses within electronic technology and facilitate device development.
Carbon Nanotubes
CNTs are tubular structures with dimensions at nanoscale, made purely from covalent carbon
interactions. CNTs can be single or multi-walled and they possess desirable properties of high electrical
conductivity, semi conductivity, mechanical strength and elasticity, thermal conduction and electron
emission.
Preparing Catalyst Films - Evaporation
CVD appears to be the most promising method for producing high yield, low cost CNTs due to low
temperatures and short growth times. The CVD method requires a catalyst to grow CNTs at these low
temperatures. A physical vapour depositor was required to fabricate an aluminium buffer and iron
catalyst onto a silicon based substrate.
Growing Carbon Nanotubes - CVD
An Aixtron Black Magic Chemical Vapour Deposition (CVD) reactor in 3W1.5a was used to grow CNTs
upon the fabricated catalysts, using a mixture of carbon containing acetylene, hydrogen gases and heat.
Potential uses:
• Energy storage
• Molecular electronics
• Thermal and structural materials
• Electrical conduction
• Fabrics and fibres
• Civil applications
• Biomedical
• Air and water filtration
• Flexible electronics
CNT properties factored by:
• Chirality
• Length
• Number of walls
• Diameter
• Purity
Results
Growth heights of every sample were measured using a microscope and compared to the conditions of
time, temperature and pressure varied in the CVD chamber.
Analysis
Comparing results from Raman spectra with results from other CNT experiments helped to conclude
that CNTs were produced and not any other allotrope of carbon.
The data collection enabled observations to be made about the most favourable conditions for growth of
CNTs, which was estimated as 600s, 750℃ and 10 mbar.
Further Research
Now that all the facilities at the university are functioning and able to grow CNTs, a larger emphasis on
data collection and analysis can be placed in further experiments. More focus can be placed onto the
factors affecting the growth mechanism and develop a recipe with optimal growth conditions for CNTs,
progressing research of CNTs and furthering their advance into electrical applications.
The CVD reactor also has the capability to grow graphene using similar techniques, which can also be
researched and explored into their applications.
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