Photovoltaic Charge Lithography on Passive Dielectric Substrates Using Fe:LiNbO3 Stamps

Abstract

Photovoltaic Fe:LiNbO₃ is an outstanding material platform able to photo-generate versatile charge patterns, useful for a broad variety of applications. However, in some cases, its photorefractive effect, light absorption, and active ferroelectric properties may interfere with the optimum operation of certain devices based on Fe:LiNbO₃. Here, a novel optoelectronic method is proposed and demonstrated to transfer photovoltaic charge patterns from Fe:LiNbO₃ to non-photovoltaic passive substrates, thus removing these possible limitations. The method, denominated as photovoltaic charge lithography (PVCL), resembles the operation of a stamp and does not require external high-voltage supplies or electron/ion beams. Upon contact between the active Fe:LiNbO₃ stamp and a passive dielectric substrate, the light-induced charge pattern can be faithfully mirrored on the passive substrate. The imprinted pattern is probed and characterized by dielectrophoretic and electrophoretic particle trapping. The results reveal that the charge builds up on the passive substrate during contact, allowing charge tunability. Moreover, arbitrary charge distributions can be flexibly tailored, using scanning laser beams or spatially structured light. Overall, PVCL opens the possibility of printing complex 1D/2D charge patterns of controlled polarity on different passive dielectric materials, enhancing the technological potential of Fe:LiNbO₃ photovoltaic platforms.