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2-Dimensional Materials

Monolayers (ML) of group IV-B transition metal dichalcogenides (TMDs) exhibit remarkable optical properties. These properties include very large exciton binding energies of several hundreds of meV, high magnetic moments and spin and valley pseudospin degrees of freedom.

Tight exciton confinement in monolayers results in fast spontaneous radiative recombination. Optical selection rules make it possible to address valley and spin degrees of freedom using polarization of light. Due to their geometry, ML TMDs can be incorporated easily into optical microcavities, photonic circuits, and flexible electronics. As a result, they have become the materials system of choice for spin-valley optoelectronics, where both spin and valley degrees of freedom are considered to be information carriers.
Here, we aim to develop photon sources; light emitting diodes based on TMDs and establish methods to confine excitons and carriers in a controlled way.

Further information:

2D Heterojunctions

Ion Implantation



Prof. Dr Beata Kardynal


Lateral heterostructures

Just as in bulk materials, charge carriers can be confined in lateral heterostructures of TMDs when areas of lower bandgap are surrounded by material of a higher bandgap. Such heterostructures could be used to fabricate a variety of photon sources or to confine electrons and excitons. Mehr: Lateral heterostructures …

MoSe2-STEM teaser

Ion Implantation

Ion implantation is a well-established technique for doping bulk semiconductors, including Si. It offers flexibility in the dopant choice; performed in high vacuum environment it is clean and compatible with most demanding electronic devices. It can also be used locally to make lateral heterostructures. In this collaborative project, funded through VolkswagenStiftung program “Integration of Molecular Components in Functional Macroscopic Systems” we are working on the adaptation of the ion implantation to monolayer materials. Our goal is to implant dilute shallow dopants to localise excitons for single photon emission but we also explore a possibility to form quantum dots by converting submicron areas of MoS2 into MoSexS(2-x). Mehr: Ion Implantation …