Multidimensional Characterization And Analysis Of Doped Copper Oxide Nanofilms Based With LIBS Technology

With the rapid development of nanoscience,a large number of functional nano films have been widely applied in different technical fields.Copper oxide（CuO）is a low-cost and excellent thin film material.Due to the copper vacancy in the structure,elemental doping becomes possible.When preparing cobalt（Co）or aluminum（Al）doped CuO thin films by Magnetron sputtering,the change of preparation parameters and processes will affect the changes in the element ratio of the thin films,which may affect the quality and performance of the thin films prepared.Therefore,it is necessary to quickly analyze the element content ratio to optimize the preparation process parameters.However,current traditional detection and analysis methods are difficult to meet the requirements of real-time,rapid,low-cost,and easy operation.Laser induced breakdown spectroscopy（LIBS）is a qualitative and quantitative analysis and detection technology of substances based on plasma emission spectroscopy.For the analysis of the composition and content of material elements,it has the advantages of real-time and rapid,without sample pretreatment,micro damage,and simultaneous detection of multiple elements.As a new analytical technology,LIBS has been widely studied and applied in many fields.In this paper,a detailed experimental research on LIBS technology in analyzing the element content ratio of doped CuO thin films has been conducted.A preliminary multi-dimensional analysis of Co-doped CuO thin films prepared by radio frequency magnetron sputtering was carried out using nanosecond laser induced breakdown spectroscopy（NS-LIBS）.Firstly,the relevant experimental parameters of Ns-LIBS were optimized for Co-doped CuO thin films,and the Co/Cu content ratios in Co-doped CuO thin films with different sputtering pressure and power parameters were quickly qualitatively and quantitatively analyzed.The fitting coefficients of the calibration curves were all above 0.99.The two-dimensional chemical mapping of the LIBS intensity ratio of Co/Cu was plotted,and the evolution relationship between the Co/Cu element emission intensity ratio of LIBS and the optical bandgap was established,It could be used to evaluate the optical properties of thin films.In addition,the calculated plasma temperature is 7298 K and the electron density is2.3×10¹⁷cm^-3not only verifies the existence of local thermodynamic equilibrium,but also ensures the accuracy of the analysis.Further multi-dimensional analysis of Al-doped CuO thin films was carried out using nanosecond and picosecond LIBS techniques.A series of Al-doped CuO thin films with different sputtering pressures and power parameters were prepared by magnetron sputtering technology to investigate the effects of doping elements on the optical properties of the thin films.Using Ns-LIBS,calibration curves of the LIBS intensity ratio to concentration ratio of Al/Cu under different sputtering pressures and power were plotted,and rapid quantitative analysis was achieved.In addition,two-dimensional chemical mappings were plotted to provide a more complete and detailed relative spatial distribution of Al elements based on the LIBS intensity ratio of Al/Cu.Besides,the profile analysis of Al-doped CuO thin films was conducted by the Ps-LIBS device,and the depth of single laser pulse ablation was close to 46.75±4.25 nm,which can achieve the evaluation of thin film thickness.Moreover,through spectral analysis of the transmittance of the thin films,it was found that the ratio of optical bandgaps to LIBS intensity has a similar trend with the variation of sputtering parameters.Using the Boltzmann bilinear method,the plasma temperature is 6102 K and the calculated electron density is1.12×10¹⁷cm^-3.The results show that LIBS can effectively achieve multidimensional characterization（quantitative analysis,two-dimensional chemical mapping,film thickness estimation,and optical property analysis）of Al doped CuO thin films prepared by RF magnetron sputtering.