Inverse Design of Ferroelectric‐Order in Perovskite Crystal for Self‐Powered Ultraviolet Photodetection

Abstract

It has always been a hot topic to design an orderly mesoscopic structure in functional materials to tailor the macroscopic properties or realize new functions. The existence of domains in ferroelectric materials has been proven to affect the macroscopic properties, being actively studied in nonlinear optical conversion and piezoelectric effects. However, the high‐efficiency photoelectric conversion capability of ferroelectric crystals has not yet been explored. Here, the authors study the orderly arrangement of ferroelectric order in KTa1−xNbxO3 (KTN) perovskite crystals, and design the “head‐to‐head” domains by tuning the Curie temperature Tc, thereby generating abundant charged domain walls and robust conductive channels for electrons and holes. An ultrahigh ultraviolet photoresponsivity is achieved in the KTN crystal under zero bias voltage, being about four orders magnitude higher than that of the well‐known ferroelectric materials. The substantial improvement can be attributed to the judiciously designed ferroelectric order, as demonstrated by the conductive atomic force microscopy. In addition, KTN detector exhibits high stability and reliability after high‐temperature and fatigue treatment. KTN crystal features giant photoresponsivity, high electric–optical coefficient, and large χ(2) nonlinearity concurrently, indicating its great potential for application of all‐optical devices on photonic chips.

Near-infrared polarization-sensitive photodetectionviainterfacial symmetry engineering of an Si/MAPbI3heterostructural single crystal

“…The built-in electric field of the heterojunction has a connatural direction pointing from the Si wafer to the MAPbI 3 SC, providing the driving force for the directional carrier transport, that is, photoexcited carriers tend to transport along the direction perpendicular to the heterogeneous interface accordingly. 34,54 When the polarized angle of the incident linearly polarized light is parallel to the direction of the built-in electric field at the MAPbI 3 /Si heterostructure interface, the largest momentum of the photogenerated carriers is generated in the direction of the built-in electric field that can enhance the ability of the separation of carriers and thus reduce the possibility of recombination, leading to a promoted photo-electric signal conversion. 55,56 Conversely, when the polarized direction of incident light is incompatible with the built-in electric field, the photocurrent will be restrained by the strong interaction between them, resulting in a decrease of the photocurrent value.…”

Transparent Lead‐Free Ferroelectric (K, Na)NbO3 Single Crystal with Giant Second Harmonic Generation and Wide Mid‐Infrared Transparency Window

“…[9] However, because of the high-density light scattering domains existing in most high-performance ferroelectrics crystals, the realization of transparent ferroelectrics crystals with giant second-harmonic generation (SHG) has long been a challenge. [10] Despite more decades of effort, ferroelectric crystals with high transparency and giant SHG have been difficult to realize. Until 2020, Qiu et al obtained transparent Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) single crystal by applying alternating current to engineer the domain structures.…”

Anomalous Optical Properties of KTN:Li Ferroelectric Supercrystals

“…Recent studies in bulk KTN show how ferroelectric domain distribution can considerably affect spectroscopic response in the visible and near-infrared spectrum [25]. To test the role of domains in the anomalous optical response, we measured SHG for a wide range of signal wavelengths [7,[26][27][28][29]. SHG conversion versus wavelength is reported in Figure 3 (see Section 4.3).…”

“…Ferroelectric KTN:Li cooled to its room-temperature phase transition manifests a ferroelectric supercrystal (SC) [1][2][3][4][5][6][7][8], a complex orderly multidomain state with the potential to provide hereto unavailable functionalities in key applicative scenarios, such as for energy and information storage [9][10][11][12]. One model of the SC is that of a volume lattice of 3D spontaneous polarization vortices (see, for example, Ref.…”