Domain-Wall p-n Junction in Lithium Niobate Thin Film on an Insulator

Domain-wall nanoelectronics has attracted extensive attention since the discovery of conductive domain walls, where domain-wall $p$-$n$ junctions are indispensable for device applications. Here, we report on the fabrication of a domain-wall $p$-$n$ junction based on $n$-type and $p$-type conductive domain walls in an $x$-cut lithium niobate thin film on an insulator using a lateral-electric-field poling technique. The electron and hole mobilities in the $n$-type and $p$-type domain walls are measured to be 337 and $93\phantom{\rule{0.2em}{0ex}}{\mathrm{cm}}^{2}\phantom{\rule{0.1em}{0ex}}{\mathrm{V}}^{\ensuremath{-}1}\phantom{\rule{0.1em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$, respectively, more than 400 times higher than those in the parent bulk crystal. The successful fabrication of a domain-wall $p$-$n$ junction with large electron and hole mobilities in the domain walls makes lithium niobate on an insulator a promising platform for domain-wall nanoelectronics and optoelectronics.