Charge writing on the nanometre scale in a fluorocarbon film

By applying voltage pulses to an atomic force microscopy cantilever, nanometre-scale charge patterns were written onto an electret surface consisting of a fluorocarbon layer grown by plasma-enhanced chemical vapour deposition on substrates with different electric conductivities. Kelvin probe force microscopy then was used to assess quantitatively the parameters relevant for optimal charge storage properties. Pulse height and duration, layer thickness and substrate, as well as the surrounding media, were varied to optimize the size of the charge patterns and their lifetime. By applying pulses of 100 mus and 25 V, lifetimes of several days were achieved with 20 nm thick fluorocarbon layers on p-doped silicon as the underlying substrate. Our process also allowed us to create localized charge patterns on metal substrates. Furthermore, for the first time, nanoscale charge patterns have been written in a liquid environment that can be used as carrier substance for particles. Copyright (C) 2002 John Wiley Sons, Ltd