Abstract
We have been developing a vacuum electrospray droplet ion (V-EDI) beam technology using electrospray of aqueous solutions in vacuum. In order to effectively utilize the V-EDI beam as a probe for ionization and sputtering in secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS), the size and charge state of the droplet ions should be optimized. However, the characteristics of the droplet ions contained in the V-EDI beams have not been fully understood. In this study, the V-EDI beams were irradiated on a smooth polymer sample for a short time, and after that, its surface was analyzed with atomic force microscopy (AFM). When the inner diameter of a source capillary used for the V-EDI beams was changed in the range of 5 to 15 μm, the size and number distributions of the impact marks and the sputtered volumes calculated from those marks were drastically changed. From these results, valuable guidelines for effectively utilizing the V-EDI beams in surface analysis were obtained.
https://ror.org/059x21724 
