Facile Preparation of PbTiO3 Nanodot Arrays: Combining Nanohybridization with Vapor Phase Reaction Sputtering

Abstract

A facile route is presented for the fabrication of spherical PbTiO3 (PTO) nanodot arrays on platinized silicon substrates using PbO vapor phase reaction sputtering on micellar monolayer films of polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) loaded with TiO2 sol–gel precursor. Short exposure to PbO transforms the amorphous TiO2 into polycrystalline PTO, while keeping the inherent size and periodicity of TiO2 nanodots. HRTEM images show that the spherical PTO nanodots, with an average size and height of 63 nm and 40 nm, respectively, are fixed on the Pt supported by residual carbon. XPS narrow scan spectra of Ti 2p and O 1s strongly verify the evolution of chemical identity and the reduction of the Ti‐O binding energy from TiO2 to PTO. The amplitude and phase images of piezoelectric force microscopy (PFM) confirm a multidomain structure attributed by the crystalline orientation of the PTO nanodots. Furthermore, the discrete PTO nanodots show remarkable switching properties due to the low strain field induced by the small lateral size, and the absence of domain pinning effects by grain boundary.

Overhanging ferroelectric nanodot arrays created by high surface energy seeds

“…Since the mid1990s, classical top-down approaches, such as focused ion beam (FIB) milling and electron beam direct writing (EBDW), have been employed to pattern surface into an array of individual ferroelectric materials [11,12]. However, for they are time-consuming and lowthroughput processes, several alternative bottom-up approaches such as dip-pen lithography and the use of block copolymers as nanoscale templates have been introduced to explore stable ferroelectric nanostructures smaller than 100 nm [13,14]. Despite such recent advances, there still lies a necessity to employ a post-annealing treatment at an elevated temperature in order to crystallize ferroelectric materials; extra caution is to be taken when doing this, since this could beget undesirable alterations in shape or in volume of the ferroelectric nanostructures.…”

Fabrication of Arrays of Lead Zirconate Titanate (PZT) Nanodots via Block Copolymer Self-Assembly

“…3,5,6,8,11 Isolated singlecrystalline ferroelectric nanostructures have shown improved memory characteristics such as high polarization retention compared to their thin film counterparts, due to the presence of single ferroelectric domains, 11 and increased electromechanical displacement due the reduction of clamping effects on 90 degree domain reorientation. 12 Techniques such as electron beam lithography, 5,6 focused ion beam milling, 12 nanoimprint lithography, 13,14 dip-pen lithography, 15 sol-gel selfassembly [16][17][18] and templating 7,11,[19][20][21] have been used successfully to fabricate arrays of discrete nanoislands or dots. Although 'top-down' lithography-based techniques have been successful in making precisely positioned ferroelectric nanodots, their inherent feature-size limitations, low throughput and high processing cost makes these techniques less prevalent.…”

“…22 While self-assembly-based 'bottom-up' methods offer facile high-throughput synthesis of ferroelectric nanoislands, they suffer from poor ordering and limited control over feature size, which limits their practical application. [16][17][18]22 Templateassisted synthesis is a simplistic low-cost route for fabricating ferroelectric nanodots, due to the number of deposition methods that can be utilized and good control over the dimensions of the nanostructures formed. 7,11,[19][20][21] For example, Lee et al 3 fabricated individually addressable epitaxial arrays of PZT nanodot capacitors (~ 60 nm in diameter and ~ 20 to 40 nm in height) with a density of 32 Gb cm -2 using anodic aluminium oxide (AAO) templates.…”

Fabrication of Highly Ordered and Well‐Aligned PbTiO3/TiN Core–Shell Nanotube Arrays

“…[ 7,8 ] In particular, ferroelectric nanostructures, such as nanotubes, [9][10][11] nanowires, [ 12,13 ] and nanodots, [ 1 ] have been widely studied to meet an increasing demand for miniaturization of electronic devices. Various methods have been proposed for the fabrication of ferroelectric nanostructures, including the template-assisted method, which is the most representative technique used to fabricate vertically aligned nanostructures.…”

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Ferroelectric materials have been widely investigated in many applications due to their unique features such as spontaneous polarization, piezoelectric, and pyroelectric properties in applications such as nonvolatile memories, [1][2][3][4] piezoelectric nanogenerators, [ 5,6 ] and sensors. [ 7,8 ] In particular, ferroelectric nanostructures, such as nanotubes, [9][10][11] nanowires, [ 12,13 ] and nanodots, [ 1 ] have been widely studied to meet an increasing demand for miniaturization of electronic devices.

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