Periodic Reporting for period 1 - DiSeTCom (Dirac Semimetals based Terahertz Components)
Reporting period: 2019-03-01 to 2021-09-30
This project aims to provide theoretical and experimental basis, to perform proof of concept experiments and to build
prototypes of the thinnest ever alignment–free components of the THz photonics. Being based on 2D Dirac semimetals
(graphene, silicene, germanene) and metamaterials paradigm, the fabricated lenses, filters and polarizers will be capable to
outdoing the existing ones in terms of performance, footprint and tunability in lab-on-chip integrated solutions. The project
relies on solid theoretical background that will enable calculation of the constituent parameters of 2D semimetals with
account for defects, doping, stacking, strain and external fields using ab initio and tight binding approaches. The advances in
nanoelectromagnetics will be employed to reveal physical phenomena underlying the response of both individual Dirac
semimetal based metaatoms and their arrays in the THz spectral range. From the experimental side, the DiSeTCom will feed
into the development of feasible and easy to use techniques for fabrication of metasurfaces based on graphene/silecene/
germanene that will lead to prototype of tunable THz passive components with unprecedented performance. Robust design
and sensitivity analysis will allow us to develop revolutionary THz devices thereby contributing to the European technology
and creativity through joint R&D and R&I multisectorial and international cooperation activities supported by knowledge sharing.
prototypes of the thinnest ever alignment–free components of the THz photonics. Being based on 2D Dirac semimetals
(graphene, silicene, germanene) and metamaterials paradigm, the fabricated lenses, filters and polarizers will be capable to
outdoing the existing ones in terms of performance, footprint and tunability in lab-on-chip integrated solutions. The project
relies on solid theoretical background that will enable calculation of the constituent parameters of 2D semimetals with
account for defects, doping, stacking, strain and external fields using ab initio and tight binding approaches. The advances in
nanoelectromagnetics will be employed to reveal physical phenomena underlying the response of both individual Dirac
semimetal based metaatoms and their arrays in the THz spectral range. From the experimental side, the DiSeTCom will feed
into the development of feasible and easy to use techniques for fabrication of metasurfaces based on graphene/silecene/
germanene that will lead to prototype of tunable THz passive components with unprecedented performance. Robust design
and sensitivity analysis will allow us to develop revolutionary THz devices thereby contributing to the European technology
and creativity through joint R&D and R&I multisectorial and international cooperation activities supported by knowledge sharing.
According to the project schedule 20 p/m visits was planned. It was expected that 13p/m will be made by the TC, 6 p/m by UEF and 1p/m by UniSa.
The target of 20 p/m in M1-M31 has been met (20.56 p/m has been done). TC made 13.8 p/m, i.e. 0.8 p/m above the plan. This was because for TC researchers it took a bit longer than expected to learn new fabrication techniques developed at the UEF. In addition, about 1 p/m was transferred from UEF to Teravil because it was practical to involve also an ESR from Teravil in acquiring new skills at the UEF. Correspondingly 6 p/m planned for UEF were reduced down to 4.56 p/m. The remaining 1.44 p/m were allocated to the visits to UEF from Teravil (1.1 p/m) and INPBSU (0.34 p/m).
Other qualitative indicators:
A) Publications: 37 (15 involve two or more project teams).
B) Invited Talks at international conferences: 18
C) Conference contributed talks: 15
D) Poster presentations: 8
E) Special sessions at conferences: 3
F) Inter-node seminars: 13
G) Project meetings/workshops: 7
H) Communications to general public 18
Deliverables achieved
• D6.1 DiSeTCom website M3
• D1.1. Data Management plan M6
• D5.1 Exploitation plan M6
• D1.2 Report on the project progress in M1-M12 M12
• D2.1 Report on the Dirac semimetals bandgap dependence on external fields M12
• D1.3 Mid-term project meeting M31
Milestones achieved
• MS1 Minutes of Mid-Term review meeting M31
• MS2 KPIs for all WPs M6
In M1-M31 the partners achieved important scientific results, which allowed us to make a significant step towards principal objectives programmed for this period. All scientific achievements are in line with Annex1. The progress towards all scientific deliverables is substantial, especially for graphene based THz components. Fabrication of THz components based on silicene and germanene needs involvement of the ToV experimental team in the experiments at INP BSU and Teravil and will be done in Period 2.
The project is progressing well despite difficulties caused travel restrictions imposed by the COVID-19. Extensive efforts by the project management team have allowed us to boost secondments (1.6 p/m for a period 01.10-30.11.2021) and continue publishing at a fast pace.
The target of 20 p/m in M1-M31 has been met (20.56 p/m has been done). TC made 13.8 p/m, i.e. 0.8 p/m above the plan. This was because for TC researchers it took a bit longer than expected to learn new fabrication techniques developed at the UEF. In addition, about 1 p/m was transferred from UEF to Teravil because it was practical to involve also an ESR from Teravil in acquiring new skills at the UEF. Correspondingly 6 p/m planned for UEF were reduced down to 4.56 p/m. The remaining 1.44 p/m were allocated to the visits to UEF from Teravil (1.1 p/m) and INPBSU (0.34 p/m).
Other qualitative indicators:
A) Publications: 37 (15 involve two or more project teams).
B) Invited Talks at international conferences: 18
C) Conference contributed talks: 15
D) Poster presentations: 8
E) Special sessions at conferences: 3
F) Inter-node seminars: 13
G) Project meetings/workshops: 7
H) Communications to general public 18
Deliverables achieved
• D6.1 DiSeTCom website M3
• D1.1. Data Management plan M6
• D5.1 Exploitation plan M6
• D1.2 Report on the project progress in M1-M12 M12
• D2.1 Report on the Dirac semimetals bandgap dependence on external fields M12
• D1.3 Mid-term project meeting M31
Milestones achieved
• MS1 Minutes of Mid-Term review meeting M31
• MS2 KPIs for all WPs M6
In M1-M31 the partners achieved important scientific results, which allowed us to make a significant step towards principal objectives programmed for this period. All scientific achievements are in line with Annex1. The progress towards all scientific deliverables is substantial, especially for graphene based THz components. Fabrication of THz components based on silicene and germanene needs involvement of the ToV experimental team in the experiments at INP BSU and Teravil and will be done in Period 2.
The project is progressing well despite difficulties caused travel restrictions imposed by the COVID-19. Extensive efforts by the project management team have allowed us to boost secondments (1.6 p/m for a period 01.10-30.11.2021) and continue publishing at a fast pace.
In the Period 1, the morphology of the DiracMA were studied by combining SEM and optical microscopy techniques. This allowed us to reveal the dependence of the carbon shell thickness, roughness and porosity on the synthesis parameters. The continuity of the Dirac semimetals shells was investigated by using STM, AFM and HRTEM measurements. The electrical conductivity of the deposited shells was compared with that obtained for plane samples.
The morphology and local electronic properties of the germanene and silicene films were studied in-situ by using STM and STS in order to verify the thickness of the films, their substrate coverage and presence of defects. In addition, X-Ray photoelectron spectroscopy helps understanding the chemical state of the Ge and Si in the film.
We were studying the formation of silicene on graphene grown on graphitized 4H-SiC(0001) and on highly oriented pyrolytic graphite (HOPG) as template substrate. Synthesis route consists of evaporating silicon under ultrahigh vacuum conditions (UHV) keeping the substrate at room temperature. In the same experimental chamber, the samples were characterized with STM, STS and XPS. From the experiments and theoretical calculations, we observed three different stable configurations on HOPG: (i) formation silicene nanosheets, (ii) 3D clusters, and (iii) Si 2D nanosheets intercalated below the first top layer of carbon atoms.
We demonstrated that replacing flat substrate with 3D structured one can increase the THz absorptance from 50% to 80-90%. The presence of an additional graphene layer in the system makes it possible to significantly change the dispersion of the electromagnetic response and increase the overall absorption level, at low frequencies in particular.
The fabricated structured graphene films showed outstanding THz performance in terms of the absorbance and bandwidth. They are the best candidates for fabrication ultra-thin and ultra-light THz components. Our experiments and numerical simulations showed that these structures are tolerant with respect to the fabrication defects and doping level of graphene and suit well requirements for scaled fabrication of THz passive components including attenuators, filters and polarizers.
A simple versatile tool for the design and fabrication of graphene-enhanced passive devices based on the laser micromachining of graphene enhanced gold-plated dielectric substrates was proposed and tested in THz frequency range. The fabricated metasurface demonstrated almost perfect absorption in the broad THz range spanning over more than one decade from 100 GHz. The obtained transmittivity is four times lower than that achievable in the flat free standing graphene sheet of the same conductivity.
The morphology and local electronic properties of the germanene and silicene films were studied in-situ by using STM and STS in order to verify the thickness of the films, their substrate coverage and presence of defects. In addition, X-Ray photoelectron spectroscopy helps understanding the chemical state of the Ge and Si in the film.
We were studying the formation of silicene on graphene grown on graphitized 4H-SiC(0001) and on highly oriented pyrolytic graphite (HOPG) as template substrate. Synthesis route consists of evaporating silicon under ultrahigh vacuum conditions (UHV) keeping the substrate at room temperature. In the same experimental chamber, the samples were characterized with STM, STS and XPS. From the experiments and theoretical calculations, we observed three different stable configurations on HOPG: (i) formation silicene nanosheets, (ii) 3D clusters, and (iii) Si 2D nanosheets intercalated below the first top layer of carbon atoms.
We demonstrated that replacing flat substrate with 3D structured one can increase the THz absorptance from 50% to 80-90%. The presence of an additional graphene layer in the system makes it possible to significantly change the dispersion of the electromagnetic response and increase the overall absorption level, at low frequencies in particular.
The fabricated structured graphene films showed outstanding THz performance in terms of the absorbance and bandwidth. They are the best candidates for fabrication ultra-thin and ultra-light THz components. Our experiments and numerical simulations showed that these structures are tolerant with respect to the fabrication defects and doping level of graphene and suit well requirements for scaled fabrication of THz passive components including attenuators, filters and polarizers.
A simple versatile tool for the design and fabrication of graphene-enhanced passive devices based on the laser micromachining of graphene enhanced gold-plated dielectric substrates was proposed and tested in THz frequency range. The fabricated metasurface demonstrated almost perfect absorption in the broad THz range spanning over more than one decade from 100 GHz. The obtained transmittivity is four times lower than that achievable in the flat free standing graphene sheet of the same conductivity.