Advancing ToF-SIMS with a Buckminsterfullerene Ion Source

Open Access
Author:
Szakal, Christopher
Graduate Program:
Chemistry
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
August 01, 2006
Committee Members:
  • Nicholas Winograd, Committee Chair
  • Andrew Ewing, Committee Member
  • Stephen James Benkovic, Committee Member
  • Carlo G Pantano, Committee Member
Keywords:
  • ion source
Abstract:
The implementation and characterization of a prototype 20 keV C60+ ion source from Ionoptika, Ltd. is described. A variety of sample systems, including atomic solids, molecular films, and water ice are examined to elucidate the sputtering and ionization characteristics of this new ion source. Sputter yield increases of two to three orders of magnitude in relation to traditionally employed atomic projectiles are reported. These high sputter yields, along with unique physical properties of the cluster ion sputtering process, are examined in detail. The resulting investigation depicts the C60+ projectile as a highly surface-sensitive primary ion that can provide three-dimensional chemical information for a variety of samples. New applications are presented that are in part responsible for a paradigm shift within the Secondary Ion Mass Spectrometry (SIMS) community to a rapidly expanding use of polyatomic primary ions such as C60+.