Humboldt-Universität zu Berlin - Faculty of Mathematics and Natural Sciences - Novel Materials


Nanomaterial round.pngInvestigated by the group are metal and semiconductor nanostructures and their hybrids by transport measurements. The nanostructures are made by bottom-up and top-down fabrication techniques. Electrical contacts to single nanostructures, such as nanowires, are made by micro- and nanolithography.

Studied are the size effects of the conductivity, magnetoresistance, thermopower and thermal conductance with respect to varying electrical fields, low- and high-magnetic fields and temperature.

Of particular interest is the determination of thermal transport properties at the nanoscale and in developing the required measurement techniques. Materials presently under investigation are metal-based (Ag, Ni, Co...), Si-based, and Bi2-based (Bi2Se3, Bi2Te3,...) nanostructures and core-shell nanowires.

Novel Materials Group
Prof. Dr. Saskia F. Fischer  email

Associated researchers
Dr. Rüdiger Mitdank  email
MSc. Mahni Müller  email

Further research topics

Ultra-thin layers | Quantum systems | Novel semiconductor materials


Selected Publications


Semimetal to semiconductor transition in Bi/TiO2 core/shell nanowires
M. Kockert, R. Mitdank, H. Moon, J. Kim, A. Mogilatenko, S. H. Moosavi, M. Kroener, P. Woias, W. Lee, and S. F. Fischer
Nanoscale Adv. 3, 263 (2021).
Short abstract

Nanometrology: Absolute Seebeck coefficient of individual silver nanowires
M. Kockert, D. Kojda, R. Mitdank, A. Mogilatenko, Z. Wang, J. Ruhhammer, M. Kroener, P. Woias, and S. F. Fischer
Scientific Reports 9, 20265 (2019).
Short abstract
Helmholtz Prize 2020 in the category “Applications”

Absolute Seebeck coefficient of thin platinum films
M. Kockert, R. Mitdank, A. Zykov, S. Kowarik, and S. F. Fischer
Journal of Applied Physics 126, 105106 (2019).
Short abstract

Perfect quintuple layer Bi2Te3 nanowires: Growth and thermoelectric properties
P. Schönherr, D. Kojda, V. Srot, S. F. Fischer, P. A. Van Aken, and T. Hesjedal
APL Mat. 5, 086110 (2017).
Short abstract

Free-standing millimetre-long Bi2Te3 sub-micron belts catalyzed by TiO2 nanoparticles
P. Schönherr, F. Zhang, D. Kojda, R. Mitdank, M. Albrecht, S. F. Fischer, and T. Hesjedal
Nanoscale Res. Lett. 11: 308 (2016).
Short abstract

Surface effects on thermoelectric properties of metallic and semiconducting nanowires
D. Kojda, R. Mitdank, S. Weidemann, A. Mogilatenko, Z. Wang, J. Ruhhammer, M. Kroener, W. Töllner, P. Woias, K. Nielsch, and S. F. Fischer
Phys. Status Solidi A 213, No. 3, 557–570 (2016).
Short abstract
Feature Article

Temperature-dependent thermoelectric properties of individual silver nanowires
D. Kojda, R. Mitdank, M. Handwerg, A. Mogilatenko, M. Albrecht, Z. Wang, J. Ruhhammer, M. Kroener, P. Woias, and S. F. Fischer
Phys. Rev. B 91, 024302 (2015).
DOI: 10.1103/PhysRevB.91.024302
Short abstract

Dielectrophoretic investigation of Bi2Te3 nanowires — a microfabricated thermoelectric characterization platform for measuring the thermoelectric and structural properties of single nanowires
Z. Wang, D. Kojda, N. Peranio, M. Kröner, R. Mitdank, K. Nielsch, W. Töllner, S. F. Fischer, S. Gutsch, M. Zacharias, O. Eibl, and P. Woias
Nanotechnology 26, 125707 (2015).
DOI: 10.1088/0957-4484/26/12/125707
Short abstract

The Effect of a Distinct Diameter Variation on the Thermoelectric Properties of Individual Bi0.39Te0.61 Nanowires
D. Kojda, R. Mitdank, A. Mogilatenko, W. Töllner, Z. Wang, M. Kröner, P. Woias, K. Nielsch, and S. F. Fischer
Semicond. Sci. Technol. 29, Special Issue, 124006 (2014).
DOI: 10.1088/0268-1242/29/12/124006
Short abstract
2014 - Highlight Article

Thermoelectric Properties Investigation of Single Nanowires by Utilizing a Thermoelectric Nanowire Characterization Platform
Z. Wang, J. Ruhhammer, S. Adhikari, R. Rostek, D. Moser, O. Paul, D. Kojda, R. Mitdank, S. F. Fischer, W. Toellner, K. Nielsch, M. Kroener, and P. Woias
Proc. IEEE NEMS 2013, 738-741 (2013).
DOI: 10.1109/NEMS.2013.6559834

Electrical conductivity and Seebeck coefficient measurements of single nanowires by utilizing a microfabricated thermoelectric nanowire characterization platform
Z. Wang, S. S. Adhikari, M. Kroener, D. Kojda, R. Mitdank, S. F. Fischer, W. Toellner, K. Nielsch, and P. Woias
IEEE 26th International Conference on Micro Electro Mechanical Systems (MEMS), 508-511, (20.-24. Jan. 2013).
DOI: 10.1109/MEMSYS.2013.6474290

Porous Nanostructures and Thermoelectric Power Measurement of Electro-Less Etched Black Silicon
G.D. Yuan, R. Mitdank, A. Mogilatenko, and S. F. Fischer
J. Phys. Chem. C 116, 13767−13773 (2012).
DOI: 10.1021/jp212427g

Enhanced magneto-thermoelectric power factor of a 70 nm Ni-nanowire
R. Mitdank, M. Handwerg, C. Steinweg, W. Töllner, M. Daub, K. Nielsch, and S. F. Fischer
J. Appl. Phys. 111, 104320 (2012).
DOI: 10.1063/1.4721896

Coherent spin dynamics in Permalloy-GaAs hybrids at room-temperature
P. E. Hohage, J. Nannen, S. Halm and G. Bacher, M. Wahle, S. F. Fischer, U. Kunze D. Reuter, and A. D. Wieck
Appl. Phys. Lett. 92, 241920 (2008).
DOI: 10.1063/1.2943279

Aging phenomena in nanopatterned permalloy wires
T. Last, M. Wahle, S. Hacia, S. F. Fischer, and U. Kunze
Physica B
384, 9-11 (2006).
DOI: 10.1016/j.physb.2006.05.022

Magnetotransport study of nanoscale Permalloy-Si tunnelling structures in lateral spin-valve geometry
S. Hacia, T. Last, S. F. Fischer, and U. Kunze
J. Phys. D: Applied Physics
37 (9), 1310-1315 (2004).
DOI: 10.1088/0022-3727/37/9/002

Optimization of nanostructured permalloy electrodes for a lateral hybrid spin-valve structure
T. Last, S. Hacia, S. F. Fischer, and U. Kunze
J. Appl. Phys.
96, 6706-6711 (2004).
DOI: 10.1063/1.1810197

Study of spin-valve operation in Permalloy-SiO2-Silicon nanostructures
S. Hacia, T. Last, S. F. Fischer, and U. Kunze
J. Supercond.: Incorperating Novel Magnetism 16 (1), 187-190 (2003).
DOI: 10.1023/A:1023242330715

Hexagonally ordered 100 nm period nickel nanowire arrays
K. Nielsch, R.B. Wehrspohn, J. Barthel, J. Kirschner, and U. Gösele, S. F. Fischer, and H. Kronmüller
Appl. Phys. Lett. 79 (9), 1360-1362 (2001).
DOI: 10.1063/1.1399006