Probe Preparation Apparatus And Technology For Tip-enhanced Raman Spectroscopy

With the exciting development of nanotechnology for manufacturing and analyzing new materials,it is not only required that the measuring instruments have the spatial resolution of nanoscale and the smaller measurement uncertainty,but also required to accurately characterize and measure the composition and structure of nanoscale materials.Tip-enhanced Raman spectroscopy(TERS)technology can meet these urgent and extensive measurement requirements.TERS is a technology that the nanoscale tip enhances light scattering,and the probe scan the surface of material.It not only obtains a significantly enhanced Raman signal in the near-field,but also improve the spectral resolution and imaging resolution of the Raman spectrum.The probe,which is the core part of TERS measurement equipment,is researched in this paper.First,the existing TERS measurement system and the key technology of tip preparation at home and abroad were investigated.The mechanism of interaction between light field and tip was analyzed,and the necessity of preparing probes for TERS was confirmed,which laid a foundation for further research work.According to the principle of preparing probe by electrochemical etching method,a set of automated TERS probe preparation device and technology was put forward.It included three parts: the mechanical experiment platform,the control circuit and the computer software.The external interference was reduced by the stable mechanical experiment platform and the outside environment.Through the combination of linear stepping motor,piezoelectric actuator,the measurement system of various self-made circuits and computer software,we can precisely monitor and adjust the electrochemical etching state of the probe.An experimental scheme for the preparation of the probe was carried out.The experimental results showed that tungsten and gold wires can be used to prepare probes.The curvature radius of the tip was within the range of(5?50)nm.The preparation time of single probe was less than 600 seconds,and the success rate of preparation was more than 80%.A variety of tip morphologies had been controlled and prepared.By using the evaporation equipment in the laboratory,a metal film with a certain thickness can be evenly coated on the probe,so that the prepared tungsten probe was better used in TERS.Finally,in order to verify the Raman spectrum measurement effect of the probe,the Raman spectra of single-walled and multi-walled carbon nanotubes samples were plotted using the TERS measurement device in the laboratory.The results of the experiment were analyzed.Polynomial fitting baseline,baseline deduction,peak fitting and other late stage data processing were carried out.The measurement report was finally obtained.