Numerical study of the structural and vibrational properties of amorphous Ta2O5 and TiO2-doped Ta2O5

Abstract

Using classical molecular dynamics simulations, we synthesized amorphous Ta2O5 and amorphous TiO2-doped Ta2O5. We show that Ta2O5 is composed primarily of six-folded Ta atoms forming octahedra that are either organized in chain-like structures or share edges or faces. When Ta2O5 is doped with TiO2, Ti atoms form equally five- and six-folded polyhedra that perturb but do not break the network structure of the glass. Performing a vibrational eigenmode analysis and projecting the eigenmodes on the rocking, stretching, and bending motions of the Ta-2O and Ta-3O bonds, we provide an atomic-scale analysis that substantiates the interpretations of Raman spectra of amorphous Ta2O5. This eigenmode analysis also reveals the key role played by Ti atoms in the 5 to 12 THz range.

Effect of elevated substrate temperature deposition on the mechanical losses in tantala thin film coatings

“…The main feature in all spectra is a large peak centered near 700 cm −1 , which is due to at least 4 separate bands according to the fit described in [44]. Molecular dynamics ( [45]) indicate this frequency range corresponds to bending and stretching movements involving 3 Ta coordinated oxygen atoms. One spectrum (deposition temperature = 480 • C) also shows a peak near 200 cm −1 indicative of crystallization [44], as already noticed in the XRD analysis (see Figure 6 ).…”

In silicobroadband mechanical spectroscopy of amorphous tantala

“…For computational reasons, we implemented Wolf truncation with a cutoff function as proposed in Ref. [57]. Each simulation consists of 2520 atoms, contained in a cubic box with periodic boundary conditions.…”

“…More specifically, amorphous tantala is an ideal candidate as a benchmark system, given the wide set of experimental, e.g., Refs. [47][48][49][50][51][52][53][54][55][56], and numerical [36,57] studies.…”

Tantalum(v) 1,3-propanediolate β-diketonate solution as a precursor to sol–gel derived, metal oxide thin films

“…In the case of amorphous Ta 2 O 5 , the band at 670 cm À1 corresponds to the bending and stretching of triple-coordinated oxygen (O-3Ta) and the band at 800 cm À1 is due to the stretching of double-coordinated oxygen (O-2Ta). 22,74 Fig . 4c shows the Raman spectra obtained from the thin tantalum oxide based layer on the a-SiO 2 substrate.…”

“…3 Aside from applications in orthopedic implants, 4 tantalum and its sister niobium form oxides which have a variety of uses, including capacitors, 5 batteries, 6,7 electrochromic windows, 8 pH and conductivity sensors, [9][10][11][12][13] surface plasmon resonance sensors, [14][15][16] ferroelectric memory devices, [17][18][19][20] corrosion resistant coatings, 21 and even gravity wave detectors. 22 During manufacturing of such devices, production inefficiencies and waste material lead to the addition of a recycling step, 23 thereby complicating the fabrication of products containing tantalum. Efforts to deposit such oxides via additive processes at relatively low temperatures, which would save material and energy, [24][25][26] still remain a challenge.…”