Synthesis of Ba₂NaNb₅O₁₅ Powders and Thin Films Using Metal Alkoxides

Abstract

Transparent and highly oriented Ba,NaNb,OIS (BNN) thin films have been prepared by using metal alkoxides. A homogeneous precursor solution was prepared by the controlled reaction of NaOC,H,, Nb(OC,H,),, and barium metal. The BNN precursor included a molecular-level mixture of NaNb(OC,H,), and Ba[Nb (OC,H,),], in ethanol. The alkoxy-derived powder crystallized to a low-temperature phase, and then transformed to orthorhombic BNN (tungsten bronze) at 600°C. BNN precursor films on substrates crystallized to orthorhombic BNN at 800°C via the low-temperature phase. Highly (002) oriented BNN films of tungsten bronze structure were successfully prepared on MgO (100) substrates at 700°C by using BNN underlayer.

Synthesis of Oriented Ba2NaNb5O15 (BNN) Thin Films from an Alkoxy‐derived Precursor

“…molecular-level mixture of BN and NN precursors in a 2:1 ratio, based on 1 H and 93 Nb NMR spectroscopy. 10 The 23 Na NMR results also support the structure of the BNN precursor.…”

“…Tungsten bronze BNN films with (002)-preferred orientation were crystallized using an underlayer of BNN on MgO(100) substrates at 700°C, as previously reported. 10 Similarly, BNN films were prepared at 700°C on Pt(100)/MgO(100) substrates using the underlayer method. Figure 3 shows the XRD profile of BNN films that have been crystallized on Pt(100)/MgO(100) substrates.…”

“…The authors previously synthesized (002)-oriented BNN films on magnesia (MgO) substrates using metal alkoxides. 10 Boulton et al 11 reported the synthesis of polycrystalline BNN films on fused silica (SiO 2 ) and platinum-sheet substrates via the sol-gel method. Alkoxy-derived precursors for tungsten bronze have been reported to crystallize in the low-temperature phase on substrates and then transform to tungsten bronze at higher temperatures.…”

“…Alkoxy-derived precursors for tungsten bronze have been reported to crystallize in the low-temperature phase on substrates and then transform to tungsten bronze at higher temperatures. 10,12,13 The lowtemperature phase has poor dielectric properties; therefore, direct crystallization of the tungsten bronze is key for the synthesis of high-quality films without any reaction between the film and the substrate, as well as nonuniform grain growth.…”