8.6 Functional Nanomaterials Sciences Cooperation Group
243
efforts will be directed to a better understanding of the charge-carrier dynamics in
perovskites combined with 2D materials for improved charge-carrier extraction, and
the optical (optoelectronic) characterisation of ultrathin 2D-perovskite layers with
eyes towards future energy harvesting applications. This research will benefit from
the core competences of several FNMS-COOP project members, the exchange of
sample material and the use of different characterisation tools. Exploiting 2D and
3D hybrid perovskite materials with their high mobilities as well as good stability and a high absorption coefficient, respectively, the combination of 2D and 3D
hybrids can be of benefit to the production of solar cells. Such combination will be
investigated jointly. In addition, the employment of 0D perovskite nanoparticles in
such schemes, which have to undergo systematic characterisation, may add further
benefits to photodetection/photovoltaic schemes.
2D-Materials Nanoscopy
To bring 2D semiconductors closer to applications and to improve the emission properties, PL enhancement has been studied since 2017 by the author’s team with the
help of co-workers from Frankfurt and Hangzhou using WS 2 on nanofabricated optical microresonators, which are achieved from ring patterns in a dielectric substrate
[80]. Previous works of the cooperation partners allowed combining both vertical
and horizontal interference effects to improve both incoupling into and outcoupling
of light from 2D materials. Photodetectors, 2D-material photovoltaics, nonlinear
optics and light-emitting diodes could strongly benefit from advances based on these
“bull’s-eye” ring patterns (or in certain applications such as integrated photonic circuits also from linear grating patterns), and this is currently under investigation. Such
structures could be at the core of future on-chip optical interconnects for light-based
information processing purposes. The cooperation partners plan to further investigate the nanoscale structure with regard to confinement effects using nanoscopy,
nanopatterning techniques and nanomaterials in order to obtain new insights into
the applicability of such in-plane microcavities (employing linear or circular Bragg
grating patterns). Here, nanoscopy (e.g. SNOM) on common 2D materials can particularly reveal the effects of patterned substrates on the spatially-modified nanoscale
emission patterns of the covering 2D-material flake.
Electrical Contacts, Microoptics and Plasmonics
Nanostructuring capabilities are the key to the success in the modern world of microand nanotechnological devices. In this context, one aim pursued within the cooperation group is to fabricate, characterise and develop sub-micrometer and micrometer
systems involving 2D materials. In fact, micro-/nanofabrication techniques are essential for realising designs of optoelectronic devices, particularly when it comes to the
achievement of electrical interconnects and integrated optics for sub-micrometer
(nano-sized) systems. Jointly, the production of nano-sized electrical contacts and
nanofabricated polymer optics shall be examined for use in connection with 2D materials, in order to improve the design of photosensitive field-effect transistors used in
electrostatically-gated photodetectors under investigation by the project partners.
Furthermore, controlled positioning of nanoparticles on 2D materials by combing
top-down electron-beam lithographic techniques with the meniscus-force-deposition
243
efforts will be directed to a better understanding of the charge-carrier dynamics in
perovskites combined with 2D materials for improved charge-carrier extraction, and
the optical (optoelectronic) characterisation of ultrathin 2D-perovskite layers with
eyes towards future energy harvesting applications. This research will benefit from
the core competences of several FNMS-COOP project members, the exchange of
sample material and the use of different characterisation tools. Exploiting 2D and
3D hybrid perovskite materials with their high mobilities as well as good stability and a high absorption coefficient, respectively, the combination of 2D and 3D
hybrids can be of benefit to the production of solar cells. Such combination will be
investigated jointly. In addition, the employment of 0D perovskite nanoparticles in
such schemes, which have to undergo systematic characterisation, may add further
benefits to photodetection/photovoltaic schemes.
2D-Materials Nanoscopy
To bring 2D semiconductors closer to applications and to improve the emission properties, PL enhancement has been studied since 2017 by the author’s team with the
help of co-workers from Frankfurt and Hangzhou using WS 2 on nanofabricated optical microresonators, which are achieved from ring patterns in a dielectric substrate
[80]. Previous works of the cooperation partners allowed combining both vertical
and horizontal interference effects to improve both incoupling into and outcoupling
of light from 2D materials. Photodetectors, 2D-material photovoltaics, nonlinear
optics and light-emitting diodes could strongly benefit from advances based on these
“bull’s-eye” ring patterns (or in certain applications such as integrated photonic circuits also from linear grating patterns), and this is currently under investigation. Such
structures could be at the core of future on-chip optical interconnects for light-based
information processing purposes. The cooperation partners plan to further investigate the nanoscale structure with regard to confinement effects using nanoscopy,
nanopatterning techniques and nanomaterials in order to obtain new insights into
the applicability of such in-plane microcavities (employing linear or circular Bragg
grating patterns). Here, nanoscopy (e.g. SNOM) on common 2D materials can particularly reveal the effects of patterned substrates on the spatially-modified nanoscale
emission patterns of the covering 2D-material flake.
Electrical Contacts, Microoptics and Plasmonics
Nanostructuring capabilities are the key to the success in the modern world of microand nanotechnological devices. In this context, one aim pursued within the cooperation group is to fabricate, characterise and develop sub-micrometer and micrometer
systems involving 2D materials. In fact, micro-/nanofabrication techniques are essential for realising designs of optoelectronic devices, particularly when it comes to the
achievement of electrical interconnects and integrated optics for sub-micrometer
(nano-sized) systems. Jointly, the production of nano-sized electrical contacts and
nanofabricated polymer optics shall be examined for use in connection with 2D materials, in order to improve the design of photosensitive field-effect transistors used in
electrostatically-gated photodetectors under investigation by the project partners.
Furthermore, controlled positioning of nanoparticles on 2D materials by combing
top-down electron-beam lithographic techniques with the meniscus-force-deposition