Study Of LIBS Analysis Technique For Nanometer Films Of Metal Oxides

Laser induced breakdown spectroscopy(LIBS)is a technique that utilizes focused laser pulse to ablate the sample, generating an intanstaneous and high-temperature plasma, and detects the spectra that plasma omitted during cooling and recombination process to analyze samples qualitatively and quantitively. Since its appearance, LIBS has been rapidly developed among various fields with its advantages including in-time and fast response time, lack of sample preparation, multi-element analysis ability and so on. But, there were many problems that need to be settled when the LIBS was applied in nanometer film analysis. Considering practical requirements, this work attempted to combinate LIBS technique with film analysis technique to deal with important scientific and technical probloms during combination. There were four components in this paper, including the design and realization of the analysis system, the effects and optimization of experimental parameters, multi-angle analysis of the plasma and the detective ability of established system.Based on nano-sized thickness of sample and the feature of micro-ablation, a laboratory LIBS system with the help of position system was established for nanometer film analysis. The stability of this system was verified and the relative standard deviation(RSD) of target peak was lower than 1.6%, which demonstrates that the system was available for single-shot detection with excellent repeatability and stability. At the same time, according to the test results, the ablation and collection system was advanced.Different parameters(such as laser energy, laser focus to sample distance(LFTSD)settings, focus condition and collection optical path and so on) were further analyzed and the results indicated that LFTSD setting was one of dominated parameters that effected laser-material interaction process and the formation and spectral emission of plasma. At low laser energy(1 mJ) and LFTSD = 0 mm, A series of Si atomic lines were selected to calculate plasma temperature(T)(17445 K). At the same time, two Si spectra(250.69 nm and 252.85 nm) and H?line were used to calculate electron density(Ne)(1.66 × 1017cm-3, 1.47 × 1017cm-3 and 7.5 × 1017cm-3), which indicated that formed plasma could satisfy some necessary LTE conditions.The established system were promoted and optimized according to some key problems during experiment. Position sensitive detector(PSD) and time- and spatial- resolution parts were emplomed to optimize crucial LFTSD and diagnosis of plasma character. With new system and prepared samples, the srability of system was texted and RSD could be to 1.5% after correction and the relations between the intensity of spectra and components concentration in sample were studied. The results indicated relations between them were displayed with good linear ralations(>90%). At last, all the achievements of LIBS analyzing film were summarized with a special focus on its innovations and the future research is predicated.