The Preparation And Application Of Aligned Carbon Nanotubes Films On Aluminum Substrates

Since the unique structure,carbon nanotubes(CNTs)have outstanding properties in the axis direction.Large numbers of studies have shown that aligned array carbon nanotubes had outstanding electrics,heat conduction and field emission properties and underlying application in the field of field emission electrode materials dispersive heat piece.Using different ways to introduce catalyst,both vertically aligned carbon nanotubes films and randomly oriented carbon nanotubes films were grown on silicon substrates by thermal decomposition of xylene.Meawhile,CNTs composite film with aluminum substrate can be obtained by the technique of transferring substrates.The structures of different carbon nanotube samples were investigated by scanning electron microscopy(SEM) and transmission electron microscopy(TEM) and produced high molar CNT composite films with aluminum substrate by ameliorating the experimental parameters.Finally,the heat conduction and field emission properties of CNTs samples have been investigated.The results are as follows:(1) Aligned and dense carbon nanotubes can be produced while the ratio of catalyst and carbon precursor is 1.5g:30ml at 850℃.The structures of CNTs respectively produced with alcohol and xylene as carbon precursor have prodigious differences,CNTs is pipy when the precursor is xylene and CNTs is ribbon when alcohol as carbon source.(2) CNTs film can be separated layer by layer from quartz substrate and reassembled on an aluminum foil substrate.CNTs in the separated film may keep up-straight shape on an aluminum foil substrate.CNTs with quartz can be transferred to the aluminum foil and obtain more array CNTs films to improve the using rate of CNTs films.(3) The interfacial contact resistance of composite film depend on the thickness of glue.The pressure on the composite film and the heating time,temperature affect directly thickness of glue.The interfacial contact resistance of composite film can fall down less than 0.3Ωwhile heating up 40minutes at 300℃. (4) The heat conductivity of composite film descends linearity along with temperature heat conductivity of composite film is 1.53W/(m.k) at 25℃,which is less than the heat conductivity of CNTs(3000W/(m.k)).(5) The field emission properties of CNTs samples have been investigated.The well-aligned CNTs film has a turn-on field of 1.15V/μm with a current density of 10μA/cm~2 and at the field of 1.81V/μm at 1mA/cm~2 current density was obtained, which can satisfy the need of FED.Its linear F-N curve shows the electron emission was field emission.