Effect Of Laser Shock On Structure And Electro-mechanical Properties Of GO Thin Films

Laser ablation of graphene oxide（GO）thin films enables microscale patterning for use in micro and nano electronic devices.However,the structure,mechanical and electrical properties of GO films under laser shock directly affect the stability and reliability of devices.In order to study the effect of ultrahigh strain rate loading on the structure and properties of GO thin films,the following studies were carried out:（1）The GO dispersion was vacuum-pumped to the filter membrane to form the GO film,which was then placed on a glass substrate for further study.The change mechanism of the film structure was revealed by the surface morphology and chemical composition characterization of the graphene oxide film.Scanning electron microscopy（SEM）,X-ray photoelectron spectroscopy（XPS）,four-probe tester and nano indentation tester were used to characterize and test the GO films before and after laser shock.The reasonable laser processing parameters were explored by testing the hardness,elastic modulus and conductivity of the film before and after the impact.The results show that:Under the CO₂laser impact of 1.14W power,the reduction of go films in the processing zone can be realized without causing ablative fracture of the films.The carbon content is the highest,the oxygen content is the lowest,the carbon/oxygen ratio is the highest,and the conductivity is the highest,which can reach 1.727×10³S/m.The elastic modulus and hardness are also the highest,which are 49.97GPa and 5.71GPa.（2）Based on the theory of continuous stiffness method,the effect of pressed strain rate on the hardness value of GO film was investigated.A series of nanoindentation tests were carried out for GO film under five different strain rates.The results show that the hardness value of GO films increases with the increase of strain rate,showing obvious correlation of strain rate,and different strain rates have no effect on the elastic modulus.（3）In view of the size effect phenomenon of GO film in the process of hardness measurement,three models,ER,PSR and Nix-Gao,were used to calculate the true hardness H₀of the film.The results show that the Nix-Gao model is closer to the true hardness value of the film,and the strain rate sensitivity index after removing the size effect is obviously smaller than the strain rate sensitivity index without the size effect.