Research On Thermal Conductance Of Thin Films Based On Graphene/Copper Composite

In the field of micro/nano electronics,all kinds of electronic devices and components become smaller and lighter.Due to the increase of the working power and density,the heat produced in the device raises quickly.The service life and reliability will be affected badly if the heat can't be released before it's too late.The heat dissipation materials play a very important role in the electronic equipment thermal management technology.The traditional heat sink materials(aluminum,silver,copper,et.al.)can't meet the requirement of current electronic equipment,the development of new high thermal conductivity heat sink materials is imperative.In this paper,a graphene/copper composite heat sink film with high thermal conductivity is designed and manufactured,a new experimental system is built to measure the thin film thermal conductivity,the measurement results show that the thermal conductivity of graphene/copper composite heat sink film is higher than the copper film.The content of this paper is summarized as follows:(1)The factors which affect the thermal conductivity of graphene are studied by the molecular dynamics simulation method.Firstly,a single layer graphene model is constructed.The thermal conductivity of graphene is calculated by the Lammps software.Secondly,the thermal conductivity of graphene in gas and solid substrate is calculated.It is found that the gas medium leads to a decrease of the thermal conductivity of graphene by about 30%.The effect of substrate on the thermal conductivity of graphene is more significant.Finally,the thermal conductivity of graphene is analyzed and summarized by phonon heat transfer.On the basis of this prediction,the thermal conductivity of graphene / copper composite heat sink film will be decreased by an order of magnitude compared with that of graphene,but it will be larger than the thermal conductivity of metal copper.(2)The graphene oxide thin films are prepared by Hummers method,on the basis of this,the graphene oxide suspension is made by the thin films.The graphene oxide copper composite films are prepared by electrophoretic deposition,Analysis on the characterization of the products is obtained by using SEM method,By analying the influence of different factors on the specimens morphology and properties of graphene oxide film,an optimal method is proposed for the preparation of graphene oxide/copper composite thin films.(3)A new experimental system is built to measure the thermal conductivity of thin films,and then the verification and error analysis of this method are competed.Finally the thermal conductivity of the graphite films and the graphene oxide/copper composites are measured by this method.The error of this method is within 3%.A film consists 1.5um thick graphene oxide grown on the 50 um thick copper thin film,it's found that the thermal conductivity of this film is 418.5W/(m?K).Research on graphene composite film cooling is a good application of the excellent thermal properties of graphene,it may be a good solution of the future high-performance electronic system heat problem.The design of the experiment system is an effective method of measuring the thermal conductivity of the thin film.