Crystal growth of layered perovskite Sr₂Nb₂O₇ and Sr₂Ta₂O₇ film by the sol-gel technique

Abstract

High dielectric and low loss capacitor thin films of Sr 2 Nb 2 O 7 (SN), Sr 2 Ta 2 O 7 (ST), and their solid solution Sr 2 (Nb x , Ta 12x ) 2 O 7 (SNT) were investigated using the sol-gel technique. The SN film grows with the (0n0) orientation in the case of heating at over 700 ± C. Heat treatment at a lower temperature results in the polycrystal ST-type structure. The SNT at x , 50% also resulted in the ST type. The dielectric constant for the SN film was 45, within 10% variation at 60.5 MV͞cm. Dielectric loss (tan d) was 0.3-0.5%. The small variation in dielectric constant and the paraelectricity with low loss are suitable for capacitor applications.

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

“…Fursenko reported a band-gap value (E g ¼4.6 eV) close to ours, for an amorphous film deposited by atomic vapor deposition on TiN/Si(001) substrate [23]. 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.…”

“…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.…”

Patterned Microstructure of Sol-Gel Derived Complex Oxides Using Soft Lithography

“…The procedure implemented is outlined in the flowchart, Figure 1, which differs from other reported methods. [10,11] Using ethylene glycol as a cross-linking agent and ethanol as a solvent, a transparent, stable sol was obtained. Although only 0.018 mol of water was added, hydrated citric acid was used, which provided the extra water needed to achieve the desired molar ratio of Sr/ Nb/H 2 O = 1:1:3.5.…”

Strontium tantalum oxides with perovskite-type structure: synthesis and dye photodecomposition properties

“…Solid oxide materials, including those with perovskite and layered perovskite structures with general formula ABO 3 have been reported as solids with very important photocatalytic properties for water-splitting decomposition [1,2]. It has been reported that substitution of the A and B sites of the perovskite-structure of these solids by cations significantly affects their semiconductor properties and, hence, their photocatalytic activity [3][4][5].…”

“…It has been reported that substitution of the A and B sites of the perovskite-structure of these solids by cations significantly affects their semiconductor properties and, hence, their photocatalytic activity [3][4][5]. Through photoluminescence studies it has been shown that when the O-M-O angles of the perovskite-type oxides approach 180°a high delocalized excitation energy was produced improving the mobility of the photogenerated electron-hole [6][7][8][9][10].…”