Structural and nanomechanical properties of sol–gel prepared (K, Na)NbO₃ thin films

Abstract

Perovskite (K, Na)NbO 3 (KNN) thin films (~100 nm) were prepared by sol-gel/spin coating process on Pt/SiO 2 /Si substrates and annealed at 650°C. The structural properties of KNN films were confirmed by X-ray diffraction analysis (XRD), Raman spectroscopy and scanning electron, transmission electron and atomic force microscopy (SEM, TEM and AFM) analysis. Pure perovskite phase of K 0.65 Na 0.35 NbO 3 in nonstoichiometric composition with monoclinic symmetry in film was revealed. Uniform homogeneous microstructure of KNN film with the roughness (~6.9 nm) contained spherical particles (~50-90 nm). Nanoindentation technique was used to characterize the mechanical properties of KNN films. Elastic modulus and hardness of Pt, SiO 2 and KNN thin films were calculated from their composite values of KNN/Pt/SiO 2 /Si film/substrate system. The modulus and hardness of KNN film (71 and 4.5 GPa) were lower in comparison with SiO 2 (100 and 7.5 GPa). Pt film (~30 nm) did not influence the composite modulus, but had effect on hardness of KNN film.

In Vitro Biocompatibility of Piezoelectric K0.5Na0.5NbO3 Thin Films on Platinized Silicon Substrates

“…Fibroblast cells exhibit increased proliferation and spreading with increasing substrate stiffness in the range from 100 Pa to 100 kPa, but they also start to produce stress fibers above 10 kPa . Yet, fibroblast cells have been reported to proliferate well on glass substrates. , The bulk Young’s moduli of the materials used in the current study are reported to be in the range of 80–170 GPa, − while for KNN films on SiPt, values between 70 and 100 GPa can be found . These values are much higher than the values typically used when studying the effect of substrate stiffness on cells and it is not clear from the literature whether the differences in such a high stiffness regime will influence cell behavior.…”

Advanced Synthesis on Lead‐Free KxNa(1−x)NbO3 Piezoceramics for Medical Imaging Applications

“…The addition of these dopants improved the polarization: the sample with 5% of Li presents a polarization of 16 μC cm −2 at 700 °C. Bruncková and co‐workers presented the deposition effect of K0. 65 Na 0.35 NbO 3 thin film in different substrates.…”

“…As demonstration of its feasibility, modified sol-gel routes were recently used to prepare, at low temperature (<600 C) leadfree KNN thin films (%100 nm) with enhanced electrical and mechanical properties. [77,78] Another interesting example is represented by Kakimoto and co-workers [79] who synthesized porous Li 0.06 (Na 0.5 K 0.5 ) 0.94 NbO 3 (LNKN-6) and the composite LNKN-6/KNbO 3 using phenol resin fiber (Kynol TM ) as templating agent. Due to the low temperature required in the annealing step, the loss of alkali was completely suppressed in this synthesis.…”

Ferroelectric and dielectric properties of Ca2+-doped and Ca2+–Ti4+co-doped K0.5Na0.5NbO3thin films

“…In only a few studies other solvents have been used, e.g. propionic acid 50 , ethanol 51 , water [52][53][54][55][56][57] and other 58,59 . Due to low cost and the ubiquity of Si in electronics, platinized silicon (SiPt, Pt/TiO2/SiO2/Si) is by far the most used substrate in ferroelectric oxide thin film CSD synthesis 17 .…”

“…Due to low cost and the ubiquity of Si in electronics, platinized silicon (SiPt, Pt/TiO2/SiO2/Si) is by far the most used substrate in ferroelectric oxide thin film CSD synthesis 17 . KNN thin film synthesis is no exception, and the majority of studies of KNN thin films are based on using SiPt substrates [19][20][21][22][23][24][28][29][30][31][32][33][34][35][36][40][41][42][43][46][47][48]52,53 , while a few other studies are reported using other substrates like SiO2/Si 38,58,59 , ZrO2/Si 44,45 , LaNiO3/Si 57 , Pt/MgO 39 , Pt/Al2O3 49,58 , metals 50,51,54 and SrTiO3 (STO) 18,[25][26][27]37,55,56 .…”