Two-dimensional structures of ferroelectric domain inversion in LiNbO3 by direct electron beam lithography

TL;DR

This study demonstrates a novel method for fabricating two-dimensional ferroelectric domain structures in LiNbO3 using direct electron beam lithography, enabling potential applications in photonic crystal devices.

Contribution

The paper introduces a room-temperature electron beam lithography technique to create 2-D ferroelectric domain patterns in LiNbO3 without static bias, including across the entire crystal thickness.

Findings

Successful fabrication of 2-D domain-inverted structures in LiNbO3

Observation of 2-D patterns on both crystal faces

Potential for creating 2-D photonic and nonlinear photonic crystals

Abstract

We report on the fabrication of domain-reversed structures in LiNbO3 by means of direct electron beam lithography at room temperature without any static bias. The LiNbO3 crystals were chemically etched after the exposure of electron beam and then, the patterns of domain inversion were characterized by atomic force microscopy (AFM). In our experiment, an interesting phenomenon occurred when the electron beam wrote a one-dimensional (1-D) grating on the negative c-face: a two-dimensional (2-D) dotted array was observed on the positive c- face, which is significant for its potential to produce 2-D and three-dimensional photonic crystals. Furthermore, we also obtained 2-D ferroelectric domain inversion in the whole LiNbO3 crystal by writing the 2-D square pattern on the negative c-face. Such a structure may be utilized to fabricate 2-D nonlinear photonic crystal. AFM demonstrates that a 2-D domain-reversed structure has been achieved not only on the negative c-face of the crystal, but also across the whole thickness of the crystal.