Ferroelectricity in Strategically Synthesized Pb-free LiNbO 3 -type ZnSnO 3 Nanostructure Arrayed Thick Films
- PDF / 2,367,816 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 83 Downloads / 189 Views
Ferroelectricity in Strategically Synthesized Pb-free LiNbO3-type ZnSnO3 Nanostructure Arrayed Thick Films Anuja Datta1, Devajyoti Mukherjee,1,2 Corisa Kons,1 Sarath Witanachchi1,2 and Pritish Mukherjee1,2 1
Florida Cluster for Advanced Smart Sensor Technologies & Department of Physics, University of South Florida, Tampa, Florida 33620, USA 2 Center for Integrated Functional Materials & Department of Physics, University of South Florida, Tampa, Florida 33620, USA ABSTRACT We report the evidence of ferroelectricity from LN-type ZnSnO3 nanostructure arrayed thick films (10 - 20 µm) on Si with remanent polarization value as high as ≈ 30 µC/cm2 in nanowire arrays. A combined pulsed-laser deposition (PLD) technique and a solvothermal synthesis scheme was adopted to effectively synthesize the nanostructured samples assisted by conducting ZnO template-layers. The similar crystal symmetry and comparable lattice parameter between ZnO and LN-type ZnSnO3 facilitated the dense growth of high-quality ZnSnO3 nanostructure arrays in the form of one-dimensional vertical nanowires, nanorods and twodimensional nanoflakes. The strategic synthesis method allowed controlled tunability of the morphology, crystallinity, and packing density of ZnSnO3 nanostructures, which in turn facilitated the measurement of ferroelectric (FE) properties using a simple sandwich-device geometry. Analyses of the FE properties in relation to the structures are presented and their potential for designing future Pb-free FE devices for non-volatile memory applications is discussed. INTRODUCTION The family of Pb-based perovskites such as Pb(Zr,Ti)O3 (PZT) has been extensively deliberated as feasible ferroelectric (FE) media owing to their high polarization and piezoelectric (PE) coefficients (remanent polarization, Pr ≈ 35 µC/cm2 at coercive field, Ec ≈ 1 kV/mm) [1,2]. However the use of toxic Pb in FE devices and the consequential environmental concerns have resulted in efforts to find novel environment-friendly materials with FE properties comparable to or even better than PZT. Advances have been made in the last few years to develop Pb-free FE materials and devices in the quest to replace Pb-based materials for electromechanical devices such as actuators, sensors, and transducers [3-10]. In specific but narrow application ranges the new materials appear adequate, but are not yet suited to replace PZT on a broader basis. As alternative materials, noncentrosymmetric (NCS) complex oxides show potential because of their symmetry-dependent FE and PE properties [4,6-11]. Recent focus is on NCS LiNbO3-type compounds; derivatives of the perovskite-type structure (ABO3) [12], because both LN-type and perovskite-type compounds possess three-dimensionally corner-sharing BO6 octahedra. The cooperative cation shift along the c-axis direction against close-packed anions,
results in high spontaneous polarization (theoretical Pr = 59 µC/cm2) in these types of oxide compounds, and makes them desirable candidates for exploring structure and morphology dependent polarizatio
Data Loading...
