Effect of TiO2 grain size on performance of Ba0.5Sr0.5TiO3 based capacitors for energy storage application

Abstract

The electrical energy storing capacity and holding capability are two major parameters of energy storage devices. The amount of stored electrical energy is directly related to capacitance and holding capability is inversely related to leakage current. Metalinsulator-metal (MIM) capacitor with suitable insulator material can achieve both of these properties. Barium strontium titanate (Ba 0.5 Sr 0.5 TiO 3) has high relative permittivity hence it is a good candidate for insulator material and can enhance specific capacitance (capacitance per unit mass) of MIM capacitor. Ba 0.5 Sr 0.5 TiO 3 is a solid solution of barium titanate (BaTiO 3) and strontium titanate (SrTiO 3) and can be synthesized by many techniques such as hydrothermal [1, 2], solid-state reaction [3, 4], spray pyrolysis [5], sol-gel [6-8], RF magnetron sputtering [9, 10] and so on. Ba 0.5 Sr 0.5 TiO 3 is ferroelectric material having high dielectric constant, high breakdown field strength, low dielectric loss, pyroelectric properties, ferroelectricity and thermal stability and hence it is suitable for applications in ferroelectric random access memories (FRAM), multi-layer ceramic capacitors, tunable filters, microwave phase shifters, opto-electronic device, sensors [11-16]. The peculiar properties of Ba 0.5 Sr 0.5 TiO 3 make it suitable for considering in energy storage devices. Being a very good insulator, Ba 0.5 Sr 0.5 TiO 3 can be used as best candidate for insulator in metal-insulator-metal (MIM) capacitors which are electrostatic capacitors having fast charging-discharging characteristics and very high lifespan. In this work, Ba 0.5 Sr 0.5 TiO 3 nanopowder has been synthesized using barium carbonate (BaCO 3) and strontium carbonate (SrCO 3) as barium and strontium precursors, respectively. Commercially available titanium dioxide (TiO 2) and TiO 2 synthesized from titanium (Ti) isopropoxide were used as titanium precursors for Ba 0.5 Sr 0.5 TiO 3 nanopowder synthesis. Hence two Ba 0.5 Sr 0.5 TiO 3 nanopowder samples were synthesized. Further Ba 0.5 Sr 0.5 TiO 3 ceramic based MIM capacitor prepared from these two Ba 0.5 Sr 0.5 TiO 3 samples were fabricated with silver as top and bottom electrodes. The specific capacitance and the leakage current density are then evaluated and compared in this paper. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Investigation of Leakage Current in Micro M-I-M Structure Using Multilayer High-K Dielectric Materials with COMSOL Multiphysics

“…As a result of the existence of impurities and imperfections in materials, dielectrics are not ideal insulators, allowing a small current to pass between the two conducting electrodes. The leakage current is a critical drawback that suffers the holding capability of the micro M-I-M capacitor [28]. It wrecks the dielectric insulation between the plates and causes energy loss.…”