Electronic material are important for an extremely broad range of applications, from piezoelectrics for actuation and sensors to thermoelectrics for energy harvesting, and tunable materials such as ferroelectrics and multiferroics for adaptable electronics. New materials are continually being developed for electronic applications, and accurate measurements of the electromagnetic properties of these often complex new materials is critical both for device design using new materials, and for the continued developement of materials-by-design.

We are developing new broadband impedance measurements of thin-film materials and devices in order to address these issues. On-wafer measurements of thin-film devices allows us to measure the impedance of planar thin-film-based structures at frequencies up to 100 GHz. When combined with more traditional impedance analysis at lower frequencies, we can obtain frequency-dependent impedance data over the extremely broad frequency range from several 100 Hz to 100 GHz. The electrical impedance of planar measurement structures can be used to extract intrinsic material quantities, such as the conductivity or dielectric permittivity and/or magnetic permeability, of the constituent thin-film materials. The material parameters describing the electromagnetic response of materials can then be combined with mechanical and thermal material properties to achieve an accurate description of material and device response over a wide range of experimental conditions, and can be used as feedback for the design of entirely new materials. We currently apply these broadband measurement techiques to study thin-film material systems such as dielectrics, ferroelectrics, multiferroics, electro-acoustics, and high-temperature superconductors.

 

key words

Broadband impedance measurements; Electronic materials; Impedance spectroscopy; Thin-film materials;

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral applicants