Thermally stable dielectric responses in uniaxially (001)-oriented CaBi4Ti4O15 nanofilms grown on a Ca2Nb3O10− nanosheet seed layer

Abstract

To realize a high-temperature capacitor, uniaxially (001)-oriented CaBi4Ti4O15 films with various film thicknesses were prepared on (100)cSrRuO3/Ca2Nb3O10− nanosheet/glass substrates. As the film thickness decreases to 50 nm, the out-of-plane lattice parameters decrease while the in-plane lattice ones increase due to the in-plane tensile strain. However, the relative dielectric constant (εr) at room temperature exhibits a negligible degradation as the film thickness decreases to 50 nm, suggesting that εr of (001)-oriented CaBi4Ti4O15 is less sensitive to the residual strain. The capacitance density increases monotonously with decreasing film thickness, reaching a value of 4.5 μF/cm2 for a 50-nm-thick nanofilm, and is stable against temperature changes from room temperature to 400 °C irrespective of film thickness. This behaviour differs from that of the widely investigated perovskite-structured dielectrics. These results show that (001)-oriented CaBi4Ti4O15 films derived using Ca2Nb3O10− nanosheets as seed layers can be made candidates for high-temperature capacitor applications by a small change in the dielectric properties against film thickness and temperature variations.

Highly Transparent and Conductive Indium‐Free Vanadates Crystallized at Reduced Temperature on Glass Using a 2D Transparent Nanosheet Seed Layer

“…NS are obtained by an exfoliation process of various layered oxides [31] and transferred by Langmuir-Blodgett (LB) method (Figure 1a,b) [32] on substrates that, when used bare, are non-adapted for complex oxide deposition, such as silicon or glass. The exceptionally rich structural diversity of NS makes them interesting growth templates for oxides [30,[33][34][35][36][37][38][39][40] or metals. [41] SVO has a cubic perovskite structure with a lattice parameter a = 0.384(1) nm [42] whereas CVO is orthorhombically (o) distorted with pseudo-cubic (pc) a pc = a o /√2 = b o /√2 = c o /2 ≈0.377(1) nm.…”

Textured Manganite Films Anywhere

“…The NS obtained by exfoliation of layered structures such as Ruddlesden–Popper phases (for instance SrLaTi 2 TaO 10 2– and Ca 2 Ta 2 TiO 10 2– ), Dion–Jacobson phases (for instance (Ca,Sr) 2 (Nb,Ta) 3 O 10 – and LaNb 2 O 7 – ), and Aurivillius phases (for instance (Sr,Bi)­Ta 2 O 7 2– and Bi 4 Ti 3 O 12 2– ) open new perspectives for the integration of oxides onto nonadapted substrates. Among the NS obtained from these layered oxides, Ca 2 Nb 3 O 10 – (CNO) has been used for the growth of various materials as TiO 2 , CaBi 4 Ti 4 O 15 , or (Na 1– x K x )­NbO 3 , SrTiO 3 , and SrRuO 3. , The Dion–Jacobson parent phase KCa 2 Nb 3 O 10 crystallized in the monoclinic system ( a = 0.7741 nm, b = 0.7707 nm, c = 1.4859 nm, β = 97.51°, JCPDS card N°01-075-9853) and is usually described in a larger tetragonal unit cell with lattice constants a = 0.7727 nm and b = 2.9466 nm. , Its structure consists of stacking of slabs of 3 perovskite layers laying in the (001) plane, separated by a cation (K + ) layer.…”

Effect of substrate temperature on the optical properties of CaBi4Ti4O15 thin films deposited by pulsed laser ablation

“…The common deposition methods to use deposit high quality of the CBTi thin films are rf magnetron sputtering system, Sol-gel process, dip-coating, polymeric precursor method, Metallo-Organic Chemical Vapour Deposition (MOCVD) etc., [7,[15][16][17]. Recently, J.Kimura et al [7] deposited oriented CBTi thin films in rf sputtering system and showed the stability of dielectric constant for high temperatures.…”

“…Recently, J.Kimura et al [7] deposited oriented CBTi thin films in rf sputtering system and showed the stability of dielectric constant for high temperatures. PLD is a simple and clean process to get high-quality uniform films.…”

“…CaBi 4 Ti 4 O 15 (CBTi) is a high-temperature lead-free ferroelectric material in the group known for its applications in memories, sensors and electro-optical devices. [3][4][5][6][7][8][9][10][11]. CBTi ceramics are prepared in different methods with doping, co-doping, addition of bismuth and microwave sintering [8][9][10][11][12][13][14][15].…”