skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Integration of highly anisotropic multiferroic BaTiO 3 –Fe nanocomposite thin films on Si towards device applications
Integration of highly anisotropic multiferroic thin films on silicon substrates is a critical step towards low-cost devices, especially high-speed and low-power consumption memories. In this work, an oxide–metal vertically aligned nanocomposite (VAN) platform has been used to successfully demonstrate self-assembled multiferroic BaTiO 3 –Fe (BTO–Fe) nanocomposite films with high structural anisotropy on Si substrates. The effects of various buffer layers on the crystallinity, microstructure, and physical properties of the BTO–Fe films have been explored. With an appropriate buffer layer design, e.g. SrTiO 3 /TiN bilayer buffer, the epitaxial quality of the BTO matrix and the anisotropy of the Fe nanopillars can be improved greatly, which in turn enhances the physical properties, including the ferromagnetic, ferroelectric, and optical response of the BTO–Fe thin films. This unique combination of properties integrated on Si offers a promising approach in the design of multifunctional nanocomposites for Si-based memories and optical devices.  more » « less
Award ID(s):
2016453 1565822
PAR ID:
10226856
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Nanoscale Advances
Volume:
2
Issue:
9
ISSN:
2516-0230
Page Range / eLocation ID:
4172 to 4178
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Transition metal nitrides such as titanium nitride (TiN) possess exceptional mechanical-, chemical-, and thermal-stability and have been utilized in a wide variety of applications ranging from super-hard, corrosion-resistive, and decorative coatings to nanoscale diffusion barriers in semiconductor devices. Despite the ongoing interest in these robust materials, there have been limited reports focused on engineering high-aspect ratio TiN-based nanocomposites with anisotropic magnetic and optical properties. To this end, we explored TiN–Fe thin films with self-assembled vertical structures integrated on Si substrates. We showed that the key physical properties of the individual components (e.g., ferromagnetism from Fe) are preserved, that vertical nanostructures promote anisotropic behavior, and interactions between TiN and Fe enable a special magneto-optical response. This TiN–Fe nanocomposite system presents a new group of complex multifunctional hybrid materials that can be integrated on Si for future Si-based memory, optical, and biocompatible devices. 
    more » « less
  2. Bi 3 MoM T O 9 (BMoM T O; M T , transition metals of Mn, Fe, Co and Ni) thin films with a layered supercell structure have been deposited on LaAlO 3 (001) substrates by pulsed laser deposition. Microstructural analysis suggests that pillar-like domains with higher transition metal concentration ( e.g. , Mn, Fe, Co and Ni) are embedded in the Mo-rich matrix with layered supercell structures. The layered supercell structure of the BMoM T O thin films accounts for the anisotropic multifunctionalities such as the magnetic easy axis along the in-plane direction, and the anisotropic optical properties. Ferroelectricity and ferromagnetism have been demonstrated in the thin films at room temperature, which confirms the multiferroic nature of the system. By varying the transition metal M T in the film, the band gaps of the BMoM T O films can be effectively tuned from 2.44 eV to 2.82 eV, while the out-of-plane dielectric constant of the thin films also varies. The newly discovered layered nanocomposite systems present their potential in ferroelectrics, multiferroics and non-linear optics. 
    more » « less
  3. null (Ed.)
    A new two-phase BaTiO 3  : La 0.7 Sr 0.3 MnO 3 nanocomposite system with a molar ratio of 8 : 2 has been grown on single crystal SrTiO 3 (001) substrates using a one-step pulsed laser deposition technique. Vertically aligned nanocomposite thin films with ultra-thin La 0.7 Sr 0.3 MnO 3 pillars embedded in the BaTiO 3 matrix have been obtained and the geometry of the pillars varies with deposition frequency. The room temperature multiferroic properties, including ferromagnetism and ferroelectricity, have been demonstrated. Anisotropic ferromagnetism and dielectric constants have been observed, which can be tuned by deposition frequencies. The tunable anisotropic optical properties originated from the conducting pillars in the dielectric matrix structure, which cause different electron transport paths. In addition, tunable band gaps have been discovered in the nanocomposites. This multiferroic and anisotropic system has shown its great potentials towards multiferroics and non-linear optics. 
    more » « less
  4. null (Ed.)
    Ag nanostructures exhibit extraordinary optical properties, which are important for photonic device integration. Herein, we deposited Ag–LiNbO 3 (LNO) nanocomposite thin films with Ag nanoparticles (NPs) embedded into the LNO matrix by the co-deposition of Ag and LNO using a pulsed laser deposition (PLD) method. The density and size of Ag NPs were tailored by varying the Ag composition. Low-density and high-density Ag–LNO nanocomposite thin films were deposited and their optical properties, such as transmittance spectra, ellipsometry measurement, as well as angle-dependent and polarization-resolved reflectivity spectra, were explored. The Ag–LNO films show surface plasmon resonance (SPR) in the visible range, tunable optical constants and optical anisotropy, which are critical for photonic device applications. 
    more » « less
  5. Magnetic and ferroelectric oxide thin films have long been studied for their applications in electronics, optics, and sensors. The properties of these oxide thin films are highly dependent on the film growth quality and conditions. To maximize the film quality, epitaxial oxide thin films are frequently grown on single‐crystal oxide substrates such as strontium titanate (SrTiO3) and lanthanum aluminate (LaAlO3) to satisfy lattice matching and minimize defect formation. However, these single‐crystal oxide substrates cannot readily be used in practical applications due to their high cost, limited availability, and small wafer sizes. One leading solution to this challenge is film transfer. In this demonstration, a material from a new class of multiferroic oxides is selected, namely bismuth‐based layered oxides, for the transfer. A water‐soluble sacrificial layer of Sr3Al2O6is inserted between the oxide substrate and the film, enabling the release of the film from the original substrate onto a polymer support layer. The films are transferred onto new substrates of silicon and lithium niobate (LiNbO3) and the polymer layer is removed. These substrates allow for the future design of electronic and optical devices as well as sensors using this new group of multiferroic layered oxide films. 
    more » « less