It is generally recognized that the ideal process for fabrication at nanoscopic level would be a bottom up type methodology such as direct writing with individual atoms and molecules.
Universally known experiments in this direction have been performed, by pushing individual atoms and molecules adsorbed on a surface, using SPMs.
Such procedure is however rather laborious and not ideal for manufacturing purposes. In this work we try to set the bases for a technique that is more suited to fabrication applications, namely driving photoionized vapour phase atoms and molecules in the electric field defined by the tip of an SPM or an array of SPMs.
The material of interest is vapourized from a solid sample by one laser pulse in a high vacuum vessel and the resulting pulse of gaseous neutral material is directed to the region of the STM tip apex; here a second laser pulse tuned on an electronic transition of the material causes selective photoionization by resonance enhanced multiple photon excitation.
The ions that are formed are then deflected by a voltage applied to the tip and are so pinned down to the substrate. We report applications of this technique to the deposition of biological macromolecules, of organic molecules of interest for molecular electronics, and of metallic atoms. The problems and difficulties related to each case are discussed and the perspectives of this technology are reviewed.