A resistless photolithography method for robust markers and electrodes

We describe a method of resistless photolithography using laser for the fabrication of microscopic markers and electrodes. A single shot of laser (355 nm, 100 mJ) is used to induce local surface melting and thus transfer a pattern from the mask (TEM grid) on to the surface of silicon. With a silicon substrate pre-coated with a layer of phosphorus, the laser pulse selectively produces doped regions that are highly conducting. The electrodes and markers thus obtained are robust and can withstand harsh chemical treatments. The utility of the marker for dip-pen nanolithography is illustrated by performing gold colloid nanopatterning.