Graduation Year


Document Type




Degree Granting Department

Electrical Engineering

Major Professor

Rudy Schlaf, Ph.D.

Committee Member

Matthias Batzill, Ph.D.

Committee Member

Jing Wang, Ph.D.


electrospray ionization, ion focussing, ion funnel, cytochrome c, faraday cup


Electrospray ionization is a technique widely used in mass spectrometry. Almost every material, specifically large molecules like proteins or polymers can be ionized directly out of solution. During the ionization process molecules are not fragmented. In this work a prototype apparatus for creating three-dimensional patterns in a ultra high vacuum environment using an electrospray ion source was optimized for higher ion currents hence deposition rate by improving the core component of the apparatus, an electrodynamic ion funnel. The major improvements are a redesigned heated vacuum inlet, modified gas flow inside the ion funnel because of sealing the ion funnel against perpendicular gas flow and a better measurement setup for the transmitted current. The transmission of the ion funnel was improved from 25% to 82% resulting in ion currents of up to 7nA (500pA before advancements) focused through the ion funnel. At this rate an area of 1 cm² can be coated with a molecular monolayer of Cytochrome C in 64 minutes.