Bachelor-/Master-/Diploma thesis
We are continuously looking for Bacholar or Master (Diploma) students. If you are interested in working in our group, please contact the responsible persons.
- Preparation of B20 transition metal silicides by flash lamp annealing
B20-type transitional metal mono-silicides (TM-Si) have attracted great attentions due recently discovered or predicted new physics e.g. Skyrmions, topological Hall effect as well as unconventional chiral Fermions. We will prepare the transition metal silicides in a different way by using flash lamp or pulsed laser melting. Trransition metal films will be deposited on Si substrates. The deposit transition metal thin films will react with Si within milli-second upun flash lamp annealing. You task is to prepare B20 alloy thin films and characterize the structural, magnetic and magneto-transport properties of the obtained samples.
Contact: Dr. Shengqiang Zhou (s.zhou(at)hzdr.de).
- 2D materials for optoelectronics and spintronics
For many 2D materials, controllable doping is still not yet solved. The ion implantation followed by thermal annealing is the most established doping technology commonly used in Si-based nanoelectronics. The development of the implantation and annealing schema for the doping of 2D materials is the main goal of current proposal and will allow to modify the conductivity (e.g. n-type or p-type doping) or valley polarization. You will use ion beam for the doping or modification of interesting 2D materials. The characterization methods include temperature dependent photoluminescence and Raman as well magnetic/magneto-transport measurements.
Contact: Dr. Slawomir Prucnal (s.prucnal(at)hzdr.de) and Dr. Shengqiang Zhou (s.zhou(at)hzdr.de).
- Superconducting Ge for quantum technology
Since the discovery of superconductivity in diamond [E. A. Ekimov, et al., Nature 428, 542 (2004)] with boron content above the equilibrium solid solubility many studies have been performed to find new “superconducting semiconductors”. Such a materials class would enable the monolithic integration of quantum and conventional electronics. Indeed, several groups found superconductivity even in the technological more relevant semiconductors like Si [E. Bustarret, et al. Nature 444, 465 (2006)], Ge [T. Herrmannsdörfer, et al., Phys. Rev. Lett. 102, 217003 (2009)] and SiC [T. Muranaka, et al., Sci. Technol. Adv. Mater., 9, 044204 (2008)] after heavy hole doping. It is an unresolved question whether superconducting semiconductor films and nanowires can be fabricated at all by todays’ top down selective doping technologies and which semiconductor-acceptor combination is most promising. Your task is to prepare superconducting, single crystalline Ge (film and nanowire) by ion implantation. You will measure the electrical and structure properties of the fabricated materials.
Contact: Dr. Slawomir Prucnal (s.prucnal(at)hzdr.de) and Dr. Shengqiang Zhou (s.zhou(at)hzdr.de).
- Single color centers in silicon
Silicon nanophotonics has become one of the most promising photonic-electronic integrated platforms triggered by high demand in the realm of information technology to increase communication and computation bandwidth. This is mostly due to the very high refractive index contrast of Si with Si-based compounds and the maturity level of the existing complementary metal–oxide–semiconductor (CMOS) technology, which enables the fabrication of photonic integrated circuitry in a highly economic way. Waveguides and photodetectors have successfully been integrated in a Si photonic chip. However, the main difficulty nowadays in obtaining a fully photonic integrated circuitry lies in the development of an efficient light source, since the indirect nature of the Si band gap hinders efficient light emission for such a purpose. Your work will be devoted to create, in a controllable manner, single color centers in silicon by ion beam irradiation with nanometer-scale precision and their further integration into high-quality photonic cavities to achieve an efficient single-photon source.
Contact: Dr. Yonder Berencen (y.berencen(at)hzdr.de).
- Hyperdoped Si by deep level impurities
The hyperdoping of semiconductors consists of introducing dopant concentrations far above the solubility limits. This can be achieved by ion implantation and pulsed laser melting. Hyperdoing leads to a broadening of dopant energy level into an impurity or intermediate band. We have recently demonstrated that hyperdoping Si with Se or Te shows promise for Si-based short-wavelength infrared photodetectors [Advanced Optical Materials 9, 2001546 (2021), Optics Express 31, 26451-26462 (2023)]. The hyperdoped semiconductors are meta-stable materials and may undergo deactivation upon thermal processing even at low temperature. Your task is to investigate the effect of rapid thermal annealing on hyperdoped Si. You will measure the structural, electrical and optical properties and find their correlation.
Contact: Dr. Yonder Berencen (y.berencen(at)hzdr.de) and Dr. Shengqiang Zhou (s.zhou(at)hzdr.de).