A New Metastable Thin‐Film Strontium Tantalate Perovskite

Abstract

A novel Sr‐Ta‐O perovskite phase has been synthesized by a chemical preparation route and crystallized on Pt‐coated SiO2/Si substrates at ∼800°C. The phase was isolated as a thin film only (not as a polycrystalline powder) and is likely metastable. SEM, EDS, XRD, EPR, and Raman analyses suggest this phase is cation‐deficient, having the formula SrxTaxO3 (x∼ 0.85). X‐ray Rietveld analysis indicates the structure to be a simple‐cubic perovskite‐type lattice; Pm3m space group, a= 3.955(2) Å, V= 61.86 Å3, Z= 1. Electrical property measurements recorded a dielectric constant k of ∼16 with a tan delta of 0.04.

Structural and photoelectrochemical properties of SrTaO2N oxynitride thin films deposited by reactive magnetron sputtering

“…This is in line with the findings of Rodriguez et al [19] Figure S5). Maintaining TS = 800°C, the film thickness was controlled by regulating sputtering time to generate thicknesses of 150 and 600 nm in addition to 300 nm.…”

High-Quality Heteroepitaxial Growth of Thin Films of the Perovskite Oxynitride CaTaO2N: Importance of Interfacial Symmetry Matching between Films and Substrates

“…The perovskite structure was evidently maintained even in the case of the film containing no N (P N 2 = 0), possibly because of the formation of cation vacancies. 28 Notably, the N/Ta ratio increased with increases in P N 2 and plateaued at approximately 1 (i.e., at an almost stoichiometric value) at P N 2 ≥ 0.075 Pa. This result suggests that the N concentration was self-limited by crystallization into the perovskite structure.…”

“…Each of these patterns confirms the epitaxial growth of (100) pc -oriented perovskite in a cube-on-cube manner, while the N/Ta ratios vary from 0 to 1 depending on P N 2 that was applied (Figure b). The perovskite structure was evidently maintained even in the case of the film containing no N ( P N 2 = 0), possibly because of the formation of cation vacancies . Notably, the N/Ta ratio increased with increases in P N 2 and plateaued at approximately 1 (i.e., at an almost stoichiometric value) at P N 2 ≥ 0.075 Pa.…”

Growth of (Sr,La)-(Ta,Ti)-O-N perovskite oxide and oxynitride films by radio frequency magnetron sputtering: Influence of the reactive atmosphere on the film structure

“…Sr 2 Ta 2 O 7 films have been obtained by Kim [17], Okuwada [18] and Kato [19] by chemical route depositions on Pt-SiO 2 /Si substrates. Rodriguez [20] underlined the appearance of intense diffracted peaks on a Sr 2 Ta 2 O 7 film but he proposed a cubic cell with Pm3m space group (a¼3.955 Å) and indexed the peaks as {100} and {1 1 0}, in accordance with Rietveld structure refinement pointing out a cation deficiency. Our results are very similar to this study, but our interpretation is different as we rather believe, according to a hypothesis that Rodriguez himself proposed, that his sample was an orthorhombic film with a preferred orientation.…”

“…The influence of the reactive gas on the structural, morphological and optical characteristics was investigated. Since the targeted composition is not reported in literature, our work is compared to the deposition of related compounds: Sr 2 (Ta,Nb) 2 O 7 deposited by chemical route [17], Sr 2 Ta 2 O 7 elaborated by chemical route [18][19][20] or atomic vapor deposition [21][22][23] and SrTaO 2 N thin films deposited by nitrogen-plasma assisted pulsed laser deposition [24]. In the present study, films were deposited on single crystalline (0 0 1)MgO substrate.…”