Growth And Photoelectric Properties Of Graphene-Like Carbon Films By Chemical Vapor Deposition

Nickel is a common catalytic metal for graphene growth,which has the characteristics of strong catalysis and high carbon solubility.However,its high catalysis and high carbon solubility often lead to a large number of graphene layers and large inhomogeneity.Aluminum is a common non-ferrous metal,which does not catalyze the growth of carbon,but has the advantages of low melting point,low carbon solubility and low cost.Combining catalytic nickel metal and non-catalytic aluminum metal to make Al-Ni substrate as Chemical Vapor Deposition(CVD)growth catalyst,it has three advantages: First,the addition of aluminum can passivate part of the active site of nickel,reduce the catalytic activity of nickel,which is conducive to the formation of three-dimensional porous membrane structure.Secondly,the addition of aluminum can reduce the amount of carbon absorbed by nickel,thus reducing the thickness of the precipitation film and reducing the film heterogeneity.Third,aluminum has a low melting point and is easy to liquefy into liquid aluminum at the general CVD growth temperature.Liquid metal is more conducive to the absorption of carbon and makes the film more uniform.Therefore,pure nickel metal and aluminium-nickel metal with different compositions were used as catalytic metals to prepare graphene-like carbon films by chemical vapor deposition method,which were then tested by Raman spectroscopy,optical microscopy,scanning electron microscopy,X-ray diffraction and electrical properties.The types and intensities of Raman characteristic peaks of graphene-like carbon films generated on different growth conditions and different metal substrates,film surface morphology and structure,substrate metal phase composition and film photoelectric properties were analyzed,mainly including the following research contents:(1)Design the pure nickel,aluminum nickel layer of different thickness(50 nm 50 nm Al/Ni,70 nm 50 nm Al/Ni and 50 nm 100 nm Al/Ni),different stacking sequence of aluminum nickel layer(50 nm 50 nm Ni/Al and 50 nm 25 nm Ni/Al / 25 nm Ni),the graphene-like carbon films were grown by chemical vapor deposition.Raman spectra show that the 2D peak strength of graphene-like carbon film is weaker with the higher aluminum content in Al-Ni substrate.The Results of X-ray diffraction show that Al-Ni mesophases are formed on different Al-Ni substrates after growing at 800 ℃.The more Al Ni phases,the weaker the catalytic activity of Al-Ni substrates.The results of optical microscopy and scanning electron microscopy show that compared with pure nickel substrate,the graphene-like carbon films grown on Al-Ni substrate are composed of many fine carbon particles,with larger surface roughness and three-dimensional porous structure.(2)The photoelectrical properties of the prepared graphene-like carbon film were tested,mainly including the conductivity test under the application of blue light and the conductivity test under the application of respiratory humidity.In the test of 405 nm blue light conductivity,the graphene-like carbon film grown on pure nickel substrate showed current gain during the irradiation process,indicating that the film has a certain response to blue light.In the test of respiratory humidity conductivity,graphene-like carbon films grown on aluminum and nickel changed from non-conductive state to conductive state after artificial respiration humidity was applied,and the current changed periodically with respiration.(3)A graphene-like carbon film growth detector with a special structure is designed,which has the characteristics of self-fusing by heating.After sputtering low melting point metal film with special tip pattern structure on sapphire substrate,fracture occurs at the junction of the device tip at a specific chemical vapor deposition growth temperature,while other parts remain intact.Liquid metal forms at the fracture tip,which increases metal catalysis and carbon absorption.Raman test shows that graphene-like carbon films grow on the fracture tip.When the blue light of 405 nm is applied to conduct the conductivity test,the current is irradiated with obvious gain phenomenon,indicating that the device has a certain absorption of blue light.It is found that the graphene-like carbon films grown on Al-Ni substrates have different properties from those grown on pure nickel.Experiments show that the graphene-like carbon films grown by CVD with the addition of metal aluminum have obvious three-dimensional porous structure and good periodic response in respiratory humidity responsiveness,which can be used to develop a high sensitivity and low power consumption respiratory monitoring device.For the graphene-like carbon film growth detector,it shows good blue light absorption after growing graphene-like carbon film,which can be used in the field of photoelectric detector in the future.