Performance-enhanced ferroelectric domain wall pyroelectric detector of X-cut thin-film LiNbO3 on insulator

Here, we demonstrate a longwave infrared pyroelectric detector of X-cut thin-film LiNbO3 on insulator, of which the performance is enhanced by a geometry-engineered coplanar electrode antenna, to harvest the infrared radiation from strong near-field confinement, and conductive domain-walls (DWs) from initial surface ferroelectric polar reversal to provide a pathway for efficiently collecting the pyroelectric charges. The film-constructed device in the surface DW structure behaves like a bulk one with the responsivity inversely proportional to the heat capacity instead, and scaling down the ferroelectric thickness allows the responsivity and speed to be engineered independently. This work paves the way for an on-chip system of ferroelectric DW detectors monolithic with the CMOS readout circuit, which is to be fabricated using the wafer's handle layer.