Research

The research philosophy of DIIL is explained.

studies local electron transport properties across microstructural defects in alloys and across internal interfaces between alloys.

The research strategy is:

In DIIL we grow bulk and thin film materials in a well-controlled manner to tune defects' structures.
In DIIL we structurally characterize the defects.
In DIIL we study the local electrical and mechanical properties of individual defects and internal interfaces' segments.
In DIIL we continuously develop the methodologies for local electrical characterization.
In DIIL we develop novel defect-design concepts.

Methodology

We prepare bulk alloys. Microstructure is tuned through chemistry, solidification and annealing.
We prepare thin films alloys. Microstructure is tuned through controlling multilayer co-sputtering and annealing processes.
We Investigate the microstructure evolution (mainly) by: XRD, SEM, EBSD, EDS, TEM.
We create internal interfaces by diffusion bonding.
We Investigate the local electrical properties by SEM in-situ local electrical measurements assisted by nanomanipulator systems.
We investigate the global electrical properties of alloys.
We develop the electrical measurements methodology by utilizing finite elements simulations using COMSOL Multiphysics.
We investigate the local mechanical properties of defects.
We interconnect the microstructure and physical properties of defects.

H. Bishara, S. Lee, T. Brink, M. Ghidelli, G. Dehm: Understanding grain boundary electrical resistivity in Cu: the effect of boundary structure. ACS Nano 15 (10), 16607-16615 (2021).
H. Bishara, M. Ghidelli, G. Dehm: Approaches to measure the resistivity of grain boundaries in metals with high sensitivity and spatial resolution: a case study employing Cu. ACS Applied Electronic Materials 2 (7), 2049-2056 (2020).
T. Luo, F. Serrano-Sánchez, H. Bishara, S. Zhang, R. Bueno Villoro, J.J. Kuo, C. Felser, C. Scheu, G. J. Snyder, J. P. Best, G. Dehm, Y. Yu, D. Raabe, C. Fu, B. Gault: Dopant-segregation to grain boundaries controls electrical conductivity of n-type NbCo (Pt) Sn half-Heusler alloy mediating thermoelectric performance. Acta Materialia, 117147 (2021).

H. Bishara, H. Tsybenko, S. Nandy, Q.K. Muhammad, T. Frömling, X. Fang, J.P. Best, G. Dehm: Dislocation-enhanced electrical conductivity in rutile TiO2 accessed by nano-mechanical doping. Scripta Materialia, 212, 114543 (2022).

Examples of SEM in-situ electrical measurements of metallic and alloy systems. Images taken from the abovementioned references.