KPFM导电探针的制备及应用

Fabrication and application of conducting probe for KPFM

开尔文探针力显微镜(KPFM)可以测量样品与探针之间的接触电势差(CPD),从而可以测得样品表面电势。为了更好地测量样品表面电势的微小变化,需要制备新型导电探针。金属铱稳定的化学性质与高导电率等特性能够稳定地测量尖端样品之间的电势差。实验使用物理气相沉积(PVD)的方法修饰硅探针,使针尖镀上一层厚度为纳米级的金属铱薄膜。在实验前使用透射电子显微镜(TEM)与能谱仪(EDS)对探针进行表征,证明针尖上确实存在纳米级厚度的金属铱薄膜。最后使用制备好的导电探针在超高真空的KPFM里进行硅表面的CPD测量,得到样品表面台阶电势图。

The Kelvin probe force microscope(KPFM)measures the contact potential difference(CPD)between the sample and the probe,allowing the surface potential of the sample to be measured.In order to better measure the small change of the surface potential of the sample,a new conducting probe is needed.The stable chemical properties and high conductivity of the metal iridium can steadily measure the potential difference between the tip samples.The silicon probe was modified by physical vapor deposition(PVD)and the tip was coated with a thin film of iridium.The probe was characterized by transmission electron microscopy(TEM)and energy spectrometer(EDS)before the experiment,and it was proved that the metal iridium film with nanometer thickness did exist on the tip.Finally,the prepared conductive probe was used to measure the silicon surface CPD in the ULTRA-high vacuum KPFM to obtain the surface step potential diagram of the sample.