Carbon Nanotube Networks as Thermally Conducting Layers
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Nanotechnology (MPNAT), MSc
Publicerad
2022
Författare
Juteräng, David
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Flexible and thermally conductive materials with microfabricated structures are important
in a number of different research fields. Different approaches for integration
of such materials into functioning devices have been implemented in a plethora of
ways. Carbon nanotube networks have been the subject of many studies due to their
remarkable physical properties, including high thermal conductivity, high electron
mobility, high Young’s modulus and their flexibility, but challenges still remain. One
hurdle to overcome is the lack of efficient bonds between nanotubes in meshes. In
this project, the viability of a nickel/carbon nanotube network have been investigated
in the context of a potential thermal spreading hybrid material.
Carbon nanotubes of with different lengths were grown on silicon substrates, dispersed
in acetone and mixed into solutions containing Nickel-oxide particles. The
blends were deposited onto new Silicon substrates where they formed networks. The
Nickel particles stuck to strands and bundles of nanotubes, forming bridges between
them. Thermal treatment of the networks were performed at different time scales in
order to study the effects of annealing on the networks. The characteristics of the
Ni/CNT networks were finally investigated using scanning electron microscopy and
Raman spectroscopy in order to study potential changes within them. An increase
of the D-peak/G-peak intensity ratio corresponding to longer thermal treatment of
the substrates were concluded to be a plausible indicator of increased bonding between
the Ni-particles and CNTs.
In addition, a simulation was made of a CNT-CNT electron tunneling junction. This
was done in order to provide the theoretical backround for the challenges regarding
CNT meshes. The lack of chemical bonds between tubes were calculated to increase
the resistance of a square CNT thin film by approximately 150%.
Beskrivning
Ämne/nyckelord
CNT, Ni, Thin film, Network, Mesh, Hybrid material, Thermal Conductance, Tunneling, Junction, Raman spectroscopy