• Schubert, Juergen
• Zander, Willi
• Poghossian, Arshak
• Schoening, Michael J.
• Gevorgian, Spartak
• Buniatyan, Vahe
• Martirosyan, Norayr
• Abouzar, Maryam

Abstract

Current interest in perovskite and perovskite-related ferroelectric materials is based on their wide range of electrical properties ranging from insulating materials, ionic and/or electronic conductors up to p- and ntype semiconductors and superconductors. Perovskite oxides of the system A1-xAx’BO3-b (A=Pb, Ba, La, Li; A’= Sr, Ca; B = Ti, Ta, Co, Fe, etc.) are used in high density dynamic random access memories (DRAM), non-volatile ferroelectric random access memories (FeRAM), ferroelectric field-effect transistors, voltage-tuneable capacitors (varactors), optical memories and electro-optic modulators, solid-oxide fuel cells, etc. In addition, due to the presence of oxygen vacancies and ionic conductivity, perovskite oxides have a high catalytic activity to oxygen reduction and oxidation and thus, are suitable for a large variety of gas and vapour sensor applications. Examples of realised devices include sensors sensitive to carbon monoxide and hydrocarbon, ethanol, acetone, humidity, etc. (Bio-)chemical sensors are widely used as powerful analytical tools in medical diagnostics, food industry, environmental monitoring, security and defence fields, etc. Exploring new materials for the high sensitive and efficient transduction of (bio-)chemical signals into a quantifiable electronic signal is of importance in biosensor research and technology. Due to the multifunctional material properties as well as the high catalytic activity and large dielectric constant, perovskite-oxide ferroelectrics represent a very attractive alternative material for the creation of chemical sensors and biosensors for liquids. While the unique dielectric, piezoelectric, pyroelectric, microwave and electro-optic properties of ferroelectrics have been well studied, to our knowledge, very little is known about the behaviour of high-k ferroelectric thinfilms in electrolyte solutions. In the present work, a pH sensor based on a field-effect capacitive EFIS (electrolyte-ferroelectricinsulator-semiconductor) structure with a thin-film perovskite-oxide gate of BaxSr1-xTiO3 (BST) composition prepared by means of pulsed laser deposition (PLD) technique has been realised and investigated for the first time. A high-temperature self-propagating synthesis (SHS) was used for the fabrication of the BST targets. In contrast to the conventional high-temperature ceramic technology, the SHS method is simple, ecologically clean, waste-less, energy-saving, high productive and cost-effective.

Topics

• density
• perovskite
• impedance spectroscopy
• Carbon
• Oxygen
• dielectric constant
• semiconductor
• laser emission spectroscopy
• random
• pulsed laser deposition