Restoration Of Graphene Oxide On Dielectric Substrate

Graphene has raised widespread concerns both in academia and industry due to its unique fascinating physical and chemical properties.However,the efficient large-scale preparation of graphene is still in urgent research.Nowadays,improved CVD methods on copper exhibits irreplaceable advantages in high quality compared to other synthesis of graphene.For electronic related applications,it is hardly inevitable that graphene on metal substrates should be transferred onto desired substrates such as SiO2/Si and quartz.However,the graphene grown from metal and subsequently transferred remains residue of PMMA and structural defects caused by the transfer process with properties that are generally far inferior to the initial grown one.At the same time,the zero band gap characteristics of graphene is also a major obstacle to its practical application.Here,we present a restoration for using ethanol as a liquid precursor to convert graphene oxide(GO)deposited on an insulating substrate into reduced graphene oxide(rGO),avoiding subsequent transfer and prepare rGO film with controllable uniform layers.Subsequently,other liquid carbon sources containing nitrogen such as acetonitrile and pyridine can be introduced to doped graphene to open its band gap,providing convenience for the application of graphene in the future.The specific contents of this paper are as follows:1.We explored the effect of remote Cu-vapor on the repair of GO film on dielectric substrate.We demonstrated that copper and Cu vapor introduced had totally different influences on the GO structure restoration for the first time.When Cu-vapor was introduced remotely,it would adsorb a portion of carbon atoms on the GO and even degrade the restoration efficiency,which was quite different from previous studies on graphene growth;2.We present a restoration for using ethanol as a liquid precursor via pressure chemical vapor deposition to convert GO deposited on an insulating substrate into rGO and produce continuous and controllable high-quality graphene films avoiding subsequent transfer process.Raman spectra showed that reaction temperature and carbon precursor content were two key factors for the structural recovery of GO.The repaired rGO displayed lower ID/IG ratio and the presence of a high and symmetrical 2D band indicating high crystallinity.In addition,by studying the repair mechanism and growth kinetics of graphene,we found that graphene would preferentially nucleate and grow on the existing graphene flakes rather than the dielectric substrate.An ultra fast preparation method was proposed that high quality graphene thin films with sheet resistance of 3.23 kΩ/sq could be obtained on dielectric substrate just in 3 min;3.We prepared continuous and controllable high-quality nitrogen doped graphene films on the dielectric substrate by using liquid carbon source of acetonitrile as the precursor.In this way,the band gap of graphene opened and the specific types of nitrogen could be controlled,providing a reliable method for the application of electronic devices in the future.