An electrospray device is disclosed. The electrospray device comprises a
substrate defining a channel between an entrance orifice on an injection
surface and an exit orifice on an ejection surface, a nozzle defined by a
portion recessed from the ejection surface surrounding the exit orifice,
and an electrode for application of an electric potential to the substrate
to optimize and generate an electrospray; and, optionally, additional
electrode(s) to further modify the electrospray.
