Spark-Gap Atomic Emission Microscopy

A new technique allowing elemental analysis of small regions of scanning tunneling microscopy (STM) substrates without loss of tip-surface registry has been developed. The technique is based on spark atomic emission spectroscopy and provides information normally unavailable from the STM. In this technique, a voltage excursion (>100 V) is used to excite the sample and cause emission. Spectra from a polished copper electrode surface are presented and discussed. Important parameters and present limitations are also discussed along with future directions for the improvement and long-term use of the technique.