Oxide thin film sensor devices for bio and chemical applications

Di-, para- , and ferroelectric microwave and sensor devices represent a major activity of 'Functional Oxide Films and Sensors'.

In contrast to bulk di/ferroelectrics, thin film di/ferroelectrics can be integrated into small complex thin film devices. As a result an improved or novel functionality in form of microwave or sensor devices can be achieved.

Furthermore, the use of thin films and, especially, epitaxially grown thin films offers the possibility to modify the dielectric or ferroelectric properties up to a certain degree. This engineering of the di/ferroelectric thin film can for instance be achieved via:

• Chemical substitution in epitaxial oxide films
• Combination of different layers, multilayer or superlattices
• Strained oxide films.

As a result permittivities and/or tunability of these systems can largely be enhanced.

The structural and electronic properties are analysed in the frequency range up THz. Additional to the basic understanding, the films are designed for various microwave and sensor applications.

Microsensors for chemical and biological analysis: Due to the vast enhancement of the permittivity in strain engineered ferroelectrics, field focusing thin film devices are designed that can serve as sensors for chemical solutions or biological objects. Due to their size these electric field sensors can be operated up to the high GHz regime. Within this project, different material and designs are tested and optimized, the compatibility with the objects under analysis is examined.

Microsensor for chemical and biological analysis

References:

R. Wördenweber, E. Hollmann, R. Kutzner, and J. Schubert
Induced ferroelectricity in strained epitaxial SrTiO3 films on various substrates
J. Appl. Phys. 102, 44119 (2007)

R. Wördenweber , E. Hollmann, R. Ott, T. Hürtgen, and Tai Keong Lee
Improved Ferroelectricity of Strained SrTiO3 Thin Films on Sapphire
J.of Electroceramics, (2007)

R. Ott, R. Wördenweber
Tunable Ferroelectric Capacities for Microwave Applications
Phys. Lett. 80 (2002) 2150

R. Ott, R. Wördenweber
Alternative Designs of Tunable Ferroelectric Capacities for Microwave Applications
Physica C 372-376 (2002) 540