G. Deligeorgis | Foundation for Research and Technology - Hellas (original) (raw)
Papers by G. Deligeorgis
Applied Physics Letters, 2002
A methodology for the heterogeneous integration of epitaxial GaAs wafers with fully processed sta... more A methodology for the heterogeneous integration of epitaxial GaAs wafers with fully processed standard bipolar complementary metal-oxide-semiconductor Si wafers is presented. The complete low-temperature wafer bonding process flow, including procedures for the Si wafer planarization and GaAs substrate removal, has been developed and evaluated. The implementation of an in-plane optical link, consisting of an edge-emitting laser diode, a waveguide and a photodiode, is demonstrated.
Journal of Micromechanics and Microengineering, 2001
This paper presents the fabrication processes for micromachined millimetre-wave devices, on two d... more This paper presents the fabrication processes for micromachined millimetre-wave devices, on two different types of semiconductor substrates. The first process uses micromachining on high-resistivity 100 oriented silicon. A three-layer dielectric membrane, with a total thickness of 1.5 µm is used as support for the millimetre-wave structures. This process was used for the manufacturing of two coupled line filters, with central operating frequencies of 38 and 77 GHz, respectively. The second process is based on GaAs micromachining. For the first time, a 2.2 µm thin GaAs/AlGaAs membrane, obtained by molecular beam epitaxy growth and micromachining of semi-insulating 100 GaAs, is used as a support for millimetre-wave filter structures. Cascaded coplanar waveguide open-end series stubs filter type structures, with central frequencies of 38 and 77 GHz, respectively, were designed and manufactured on a GaAs micromachined substrate. 'On wafer' measurements for the filter structures were performed. Losses of less than 1.5 dB at 38 GHz and less than 2 dB at 77 GHz have been obtained for both the silicon as well as for the GaAs-based micromachined filters.
Solid-State Electronics, 2012
In this work, a modified, lumped element graphene field effect device model is presented. The mod... more In this work, a modified, lumped element graphene field effect device model is presented. The model is based on the "Top-of-the-barrier" approach which is usually valid only for ballistic graphene nanotransistors. Proper modifications are introduced to extend the model's validity so that it accurately describes both ballistic and diffusive graphene devices. The model is compared to data already presented in the literature. It is shown that a good agreement is obtained for both nano-sized and large area graphene based channels. Accurate prediction of Drain current and transconductance for both cases is obtained.
Microelectronics, Microsystems and Nanotechnology - Papers Presented at MMN 2000, 2001
2000 International Semiconductor Conference. 23rd Edition. CAS 2000 Proceedings (Cat. No.00TH8486), 2000
A. ~ ii ~ ~ er ' , G. Constantiniclis',... more A. ~ ii ~ ~ er ' , G. Constantiniclis', F. Giaccomozzi', M. ~agadas', G. Dcligcorgis', S. ~ort~ancscul, ... 11. Vasilachc', K. Marcelli", G. Dartolucci' , D Ncculoiu', I'. Blondy" and L). Dascalul ... 'IMT Bucharest, PO Box 38-160, Bucharest Romania, 'FORTH lESL Hcraklion, ...
12th International Conference on Semiconducting and Insulating Materials, 2002. SIMC-XII-2002., 2002
George Deligeorgis', Spyros Gallis', Maria Androulidakil, Dorin Cengher... more George Deligeorgis', Spyros Gallis', Maria Androulidakil, Dorin Cengherl, Zahanas Hatzopoulos', Marin Alexe', Viorel Dragoi', Efstathios D. Kyriakis-Bitzaros', George Halkias', Francisca Peiro4 and Alexandros Georgakilas' ... ' Microelectronics Research Group, FORTH, IESL ...
2001 International Semiconductor Conference. CAS 2001 Proceedings (Cat. No.01TH8547), 2001
A new process for wafer scale integration of GaAs optoelectronic devices with Si integrated circu... more A new process for wafer scale integration of GaAs optoelectronic devices with Si integrated circuits has been investigated, based on low temperature bonding of epitaxial GaAs wafers onto planarized fully processed CMOS/BiCMOS wafers. The basic process flow and the most important aspects of the work concerning the III-V material and devices are presented
Proceedings. International Semiconductor Conference, 2002
Summary form only given. Cost-effective wavelength-tunable laser diodes (LDs) can become crucial ... more Summary form only given. Cost-effective wavelength-tunable laser diodes (LDs) can become crucial components in optical telecommunications. There are currently several technologically interesting solutions to achieve tunability based on temperature, external cavity laser, or a multi-section DBR laser. In this work we explore an alternative approach, where the LD tuning mechanism is based on the quantum-confined Stark effect (QCSE). To achieve
2000 International Semiconductor Conference. 23rd Edition. CAS 2000 Proceedings (Cat. No.00TH8486), 2000
The use of a single growth epitaxial structure was investigated for planar integration of GaAs-ba... more The use of a single growth epitaxial structure was investigated for planar integration of GaAs-based laser diodes and photodetectors. Cleaved mirror lasers, non-guided wave and guided wave photodetectors were fabricated and measured, for structure optimization. A BCl3 RIE process was developed and lasers with RIE etched mirrors were fabricated exhibiting a threshold current density less than 1 kA/cm2
2003 International Semiconductor Conference. CAS 2003 Proceedings (IEEE Cat. No.03TH8676), 2003
... References [I] A. Muller, 1. Petnni, V. Avramescu, S. lordanescu, R. Marcelli, V. Follieti. .... more ... References [I] A. Muller, 1. Petnni, V. Avramescu, S. lordanescu, R. Marcelli, V. Follieti. ... 2001 [IO] G. Bartolucci. D. Neculoiu, M. Dragoman, F. Giacomozzi, R. Marcelli, A. Muller, Modeling, Design and Characterization of Micromachined Millimeter Wave Band-pass Filters, Inl. ...
Materials Science and Engineering B: Solid-State Materials for Advanced Technology, 2001
Reactive ion etching (RIE) was used for the fabrication of GaAs/AlGaAs optoelectronic devices (la... more Reactive ion etching (RIE) was used for the fabrication of GaAs/AlGaAs optoelectronic devices (laser diodes and photodetectors) for optical interconnect applications. Smooth, vertical sidewalls with a smooth surface at the field were obtained after optimizing RIE conditions in BCl 3 -formed plasma. Accurate in-situ monitoring of the etching process was realized by laser interferometry end-point detection. This led to good process control and reproducibility of the demanding fabrication of the optoelectronic devices. The RIE etching process did not affect the electrical properties of the device by increasing the surface recombination currents. Lasers with etched mirrors exhibited a threshold current density of 970 A cm − 2 , which is one of the best values ever reported. The feasibility of a simple technology for the fabrication of optoelectronic circuits, based on a BCl 3 RIE process for laser mirror etching, has been demonstrated. : S 0 9 2 1 -5 1 0 7 ( 0 0 ) 0 0 5 9 3 -6
Proceedings of the International Semiconductor Conference, CAS, 2010
... 247, 2010, pp. 896-902. [31] [31] P. Nemes-Incze, G. Magda, K. Kamarás, and L. Biró, Crystal... more ... 247, 2010, pp. 896-902. [31] [31] P. Nemes-Incze, G. Magda, K. Kamarás, and L. Biró, Crystallographically selective nanopatterning of graphene on SiO2, Nano Research, 3, pp. 110116, Feb. 2010. ... 0135123, Jan. 2010. [40] S. Russo, M. Craciun, M. Yamamoto, A. Morpurgo ...
AIP Conference Proceedings, 2011
We report on single dot spectroscopy of (211) B InAs quantum dots, grown by molecular beam epitax... more We report on single dot spectroscopy of (211) B InAs quantum dots, grown by molecular beam epitaxy. The dots exhibit sharp emission lines, the origin of which has been identified. Polarization dependent microphotoluminescence spectra confirm fine structure splittings from 20μeV down to the determination limit of our setup (10 μeV).
Solid-State Electronics, 2012
In this work, a modified, lumped element graphene field effect device model is presented. The mod... more In this work, a modified, lumped element graphene field effect device model is presented. The model is based on the "Top-of-the-barrier" approach which is usually valid only for ballistic graphene nanotransistors. Proper modifications are introduced to extend the model's validity so that it accurately describes both ballistic and diffusive graphene devices. The model is compared to data already presented in the literature. It is shown that a good agreement is obtained for both nano-sized and large area graphene based channels. Accurate prediction of Drain current and transconductance for both cases is obtained.
Proceedings. International Semiconductor Conference, 2002
... A.Muller, R.Marcelli, I.Petrini, V.Avramescu, S.Iordanescu, S.Petrocco, L.Scopa, C.Risi, D.Va... more ... A.Muller, R.Marcelli, I.Petrini, V.Avramescu, S.Iordanescu, S.Petrocco, L.Scopa, C.Risi, D.Vasilache, European Semiconductor, 11, 27, 1997. A.Muller, D.Dascalu, D.Neculoiu , S.Iordanescu, I.Petrini, V.Avramescu, D.Vasilache, R.Marcelli, Proc. of MME'98, pp. ...
CAS 2010 Proceedings (International Semiconductor Conference), 2010
CAS 2010 Proceedings (International Semiconductor Conference), 2010
Analytical and finite element models of sub-micron Film Bulk Acoustic Resonator (FBAR) based on G... more Analytical and finite element models of sub-micron Film Bulk Acoustic Resonator (FBAR) based on GaN are reported. The analytical modelling is based on Mason's model for three composite layer FBAR structure. The numerical modelling shows good agreement with theoretical and experimental results previously obtained on FBAR operating around 6 GHz.
Science, 2012
Strong coupling of photons to the interband exciton transition in a semiconductor microcavity lea... more Strong coupling of photons to the interband exciton transition in a semiconductor microcavity leads to the formation of polaritons, bosonic quasiparticles whose properties are governed by their mixed light-matter composition. Owing to their quantum indistinguishability and the interplay of their Coulomb interactions, microcavity polaritons show unusually strong light-matter interactions and many-body quantum effects. In particular their small effective mass allows observation of quantum degeneracy effects at temperatures from 10-300K, such as Bosecondensation (1-4) and superfluidity flow dynamics (5), while their tuneable interactions make them ideal candidates for future quantum optoelectronic devices (6) working at room temperature (7). By contrast, spatially separating the electron and holes in coupled double quantum wells yields indirect excitons with long-enough lifetime for thermalisation and a large static dipole moment (8) allowing for efficient in-plane electrostatic traps (9, 10) and the coherent control of electron spins (11). By embedding double quantum wells inside a conventional microcavity in the strong coupling regime, we unite the concepts of indirect excitons and microcavity polaritons to produce optically-active quasiparticles with transport properties, named dipolaritons. These offer the advantages of both systems: electrical trapping and tuning of excitons, strong optical coupling to low-mass quasiparticles with large de Broglie wavelength, and excellent control over the dipole properties and interactions .
Physical Review Letters, 2014
We report observation of oscillations in the dynamics of a microcavity polariton condensate forme... more We report observation of oscillations in the dynamics of a microcavity polariton condensate formed under pulsed nonresonant excitation. While oscillations in a condensate have always been attributed to Josephson mechanisms due to a chemical potential unbalance, here we show that under some localization conditions of the condensate, they may arise from relaxation oscillations, a pervasive classical dynamics that repeatedly provokes the sudden decay of a reservoir, shutting off relaxation as the reservoir is replenished. Using nonresonant excitation, it is thus possible to obtain condensate injection pulses with a record frequency of 0.1 THz.
Physical Review B, 2012
A polariton condensate transistor switch is realized through optical excitation of a microcavity ... more A polariton condensate transistor switch is realized through optical excitation of a microcavity ridge with two beams. The ballistically ejected polaritons from a condensate formed at the source are gated using the 20 times weaker second beam to switch on and off the flux of polaritons. In the absence of the gate beam the small builtin detuning creates potential landscape in which ejected polaritons are channelled toward the end of the ridge where they condense. The low loss photon-like propagation combined with strong nonlinearities associated with their excitonic component makes polariton based transistors particularly attractive for the implementation of all-optical integrated circuits. 71.36.+c Contemporary electronics face ever increasing obstacles in achieving higher speeds of operation. Down-scaling which has served Moore's law for decades is approaching the inherent limits of semiconductor materials . Even though a number of novel approaches have managed to improve operating frequency and power consumption, it is commonly acknowledged that in the future, charged carriers will have to be replaced by information carriers that do not suffer from scattering, capacitance and resistivity effects. Although photonic circuits have been proposed, a viable optical analogue to an electronic transistor has yet to be identified as switching and operating powers of these devices are typically high .
Applied Physics Letters, 2002
A methodology for the heterogeneous integration of epitaxial GaAs wafers with fully processed sta... more A methodology for the heterogeneous integration of epitaxial GaAs wafers with fully processed standard bipolar complementary metal-oxide-semiconductor Si wafers is presented. The complete low-temperature wafer bonding process flow, including procedures for the Si wafer planarization and GaAs substrate removal, has been developed and evaluated. The implementation of an in-plane optical link, consisting of an edge-emitting laser diode, a waveguide and a photodiode, is demonstrated.
Journal of Micromechanics and Microengineering, 2001
This paper presents the fabrication processes for micromachined millimetre-wave devices, on two d... more This paper presents the fabrication processes for micromachined millimetre-wave devices, on two different types of semiconductor substrates. The first process uses micromachining on high-resistivity 100 oriented silicon. A three-layer dielectric membrane, with a total thickness of 1.5 µm is used as support for the millimetre-wave structures. This process was used for the manufacturing of two coupled line filters, with central operating frequencies of 38 and 77 GHz, respectively. The second process is based on GaAs micromachining. For the first time, a 2.2 µm thin GaAs/AlGaAs membrane, obtained by molecular beam epitaxy growth and micromachining of semi-insulating 100 GaAs, is used as a support for millimetre-wave filter structures. Cascaded coplanar waveguide open-end series stubs filter type structures, with central frequencies of 38 and 77 GHz, respectively, were designed and manufactured on a GaAs micromachined substrate. 'On wafer' measurements for the filter structures were performed. Losses of less than 1.5 dB at 38 GHz and less than 2 dB at 77 GHz have been obtained for both the silicon as well as for the GaAs-based micromachined filters.
Solid-State Electronics, 2012
In this work, a modified, lumped element graphene field effect device model is presented. The mod... more In this work, a modified, lumped element graphene field effect device model is presented. The model is based on the "Top-of-the-barrier" approach which is usually valid only for ballistic graphene nanotransistors. Proper modifications are introduced to extend the model's validity so that it accurately describes both ballistic and diffusive graphene devices. The model is compared to data already presented in the literature. It is shown that a good agreement is obtained for both nano-sized and large area graphene based channels. Accurate prediction of Drain current and transconductance for both cases is obtained.
Microelectronics, Microsystems and Nanotechnology - Papers Presented at MMN 2000, 2001
2000 International Semiconductor Conference. 23rd Edition. CAS 2000 Proceedings (Cat. No.00TH8486), 2000
A. ~ ii ~ ~ er ' , G. Constantiniclis',... more A. ~ ii ~ ~ er ' , G. Constantiniclis', F. Giaccomozzi', M. ~agadas', G. Dcligcorgis', S. ~ort~ancscul, ... 11. Vasilachc', K. Marcelli", G. Dartolucci' , D Ncculoiu', I'. Blondy" and L). Dascalul ... 'IMT Bucharest, PO Box 38-160, Bucharest Romania, 'FORTH lESL Hcraklion, ...
12th International Conference on Semiconducting and Insulating Materials, 2002. SIMC-XII-2002., 2002
George Deligeorgis', Spyros Gallis', Maria Androulidakil, Dorin Cengher... more George Deligeorgis', Spyros Gallis', Maria Androulidakil, Dorin Cengherl, Zahanas Hatzopoulos', Marin Alexe', Viorel Dragoi', Efstathios D. Kyriakis-Bitzaros', George Halkias', Francisca Peiro4 and Alexandros Georgakilas' ... ' Microelectronics Research Group, FORTH, IESL ...
2001 International Semiconductor Conference. CAS 2001 Proceedings (Cat. No.01TH8547), 2001
A new process for wafer scale integration of GaAs optoelectronic devices with Si integrated circu... more A new process for wafer scale integration of GaAs optoelectronic devices with Si integrated circuits has been investigated, based on low temperature bonding of epitaxial GaAs wafers onto planarized fully processed CMOS/BiCMOS wafers. The basic process flow and the most important aspects of the work concerning the III-V material and devices are presented
Proceedings. International Semiconductor Conference, 2002
Summary form only given. Cost-effective wavelength-tunable laser diodes (LDs) can become crucial ... more Summary form only given. Cost-effective wavelength-tunable laser diodes (LDs) can become crucial components in optical telecommunications. There are currently several technologically interesting solutions to achieve tunability based on temperature, external cavity laser, or a multi-section DBR laser. In this work we explore an alternative approach, where the LD tuning mechanism is based on the quantum-confined Stark effect (QCSE). To achieve
2000 International Semiconductor Conference. 23rd Edition. CAS 2000 Proceedings (Cat. No.00TH8486), 2000
The use of a single growth epitaxial structure was investigated for planar integration of GaAs-ba... more The use of a single growth epitaxial structure was investigated for planar integration of GaAs-based laser diodes and photodetectors. Cleaved mirror lasers, non-guided wave and guided wave photodetectors were fabricated and measured, for structure optimization. A BCl3 RIE process was developed and lasers with RIE etched mirrors were fabricated exhibiting a threshold current density less than 1 kA/cm2
2003 International Semiconductor Conference. CAS 2003 Proceedings (IEEE Cat. No.03TH8676), 2003
... References [I] A. Muller, 1. Petnni, V. Avramescu, S. lordanescu, R. Marcelli, V. Follieti. .... more ... References [I] A. Muller, 1. Petnni, V. Avramescu, S. lordanescu, R. Marcelli, V. Follieti. ... 2001 [IO] G. Bartolucci. D. Neculoiu, M. Dragoman, F. Giacomozzi, R. Marcelli, A. Muller, Modeling, Design and Characterization of Micromachined Millimeter Wave Band-pass Filters, Inl. ...
Materials Science and Engineering B: Solid-State Materials for Advanced Technology, 2001
Reactive ion etching (RIE) was used for the fabrication of GaAs/AlGaAs optoelectronic devices (la... more Reactive ion etching (RIE) was used for the fabrication of GaAs/AlGaAs optoelectronic devices (laser diodes and photodetectors) for optical interconnect applications. Smooth, vertical sidewalls with a smooth surface at the field were obtained after optimizing RIE conditions in BCl 3 -formed plasma. Accurate in-situ monitoring of the etching process was realized by laser interferometry end-point detection. This led to good process control and reproducibility of the demanding fabrication of the optoelectronic devices. The RIE etching process did not affect the electrical properties of the device by increasing the surface recombination currents. Lasers with etched mirrors exhibited a threshold current density of 970 A cm − 2 , which is one of the best values ever reported. The feasibility of a simple technology for the fabrication of optoelectronic circuits, based on a BCl 3 RIE process for laser mirror etching, has been demonstrated. : S 0 9 2 1 -5 1 0 7 ( 0 0 ) 0 0 5 9 3 -6
Proceedings of the International Semiconductor Conference, CAS, 2010
... 247, 2010, pp. 896-902. [31] [31] P. Nemes-Incze, G. Magda, K. Kamarás, and L. Biró, Crystal... more ... 247, 2010, pp. 896-902. [31] [31] P. Nemes-Incze, G. Magda, K. Kamarás, and L. Biró, Crystallographically selective nanopatterning of graphene on SiO2, Nano Research, 3, pp. 110116, Feb. 2010. ... 0135123, Jan. 2010. [40] S. Russo, M. Craciun, M. Yamamoto, A. Morpurgo ...
AIP Conference Proceedings, 2011
We report on single dot spectroscopy of (211) B InAs quantum dots, grown by molecular beam epitax... more We report on single dot spectroscopy of (211) B InAs quantum dots, grown by molecular beam epitaxy. The dots exhibit sharp emission lines, the origin of which has been identified. Polarization dependent microphotoluminescence spectra confirm fine structure splittings from 20μeV down to the determination limit of our setup (10 μeV).
Solid-State Electronics, 2012
In this work, a modified, lumped element graphene field effect device model is presented. The mod... more In this work, a modified, lumped element graphene field effect device model is presented. The model is based on the "Top-of-the-barrier" approach which is usually valid only for ballistic graphene nanotransistors. Proper modifications are introduced to extend the model's validity so that it accurately describes both ballistic and diffusive graphene devices. The model is compared to data already presented in the literature. It is shown that a good agreement is obtained for both nano-sized and large area graphene based channels. Accurate prediction of Drain current and transconductance for both cases is obtained.
Proceedings. International Semiconductor Conference, 2002
... A.Muller, R.Marcelli, I.Petrini, V.Avramescu, S.Iordanescu, S.Petrocco, L.Scopa, C.Risi, D.Va... more ... A.Muller, R.Marcelli, I.Petrini, V.Avramescu, S.Iordanescu, S.Petrocco, L.Scopa, C.Risi, D.Vasilache, European Semiconductor, 11, 27, 1997. A.Muller, D.Dascalu, D.Neculoiu , S.Iordanescu, I.Petrini, V.Avramescu, D.Vasilache, R.Marcelli, Proc. of MME'98, pp. ...
CAS 2010 Proceedings (International Semiconductor Conference), 2010
CAS 2010 Proceedings (International Semiconductor Conference), 2010
Analytical and finite element models of sub-micron Film Bulk Acoustic Resonator (FBAR) based on G... more Analytical and finite element models of sub-micron Film Bulk Acoustic Resonator (FBAR) based on GaN are reported. The analytical modelling is based on Mason's model for three composite layer FBAR structure. The numerical modelling shows good agreement with theoretical and experimental results previously obtained on FBAR operating around 6 GHz.
Science, 2012
Strong coupling of photons to the interband exciton transition in a semiconductor microcavity lea... more Strong coupling of photons to the interband exciton transition in a semiconductor microcavity leads to the formation of polaritons, bosonic quasiparticles whose properties are governed by their mixed light-matter composition. Owing to their quantum indistinguishability and the interplay of their Coulomb interactions, microcavity polaritons show unusually strong light-matter interactions and many-body quantum effects. In particular their small effective mass allows observation of quantum degeneracy effects at temperatures from 10-300K, such as Bosecondensation (1-4) and superfluidity flow dynamics (5), while their tuneable interactions make them ideal candidates for future quantum optoelectronic devices (6) working at room temperature (7). By contrast, spatially separating the electron and holes in coupled double quantum wells yields indirect excitons with long-enough lifetime for thermalisation and a large static dipole moment (8) allowing for efficient in-plane electrostatic traps (9, 10) and the coherent control of electron spins (11). By embedding double quantum wells inside a conventional microcavity in the strong coupling regime, we unite the concepts of indirect excitons and microcavity polaritons to produce optically-active quasiparticles with transport properties, named dipolaritons. These offer the advantages of both systems: electrical trapping and tuning of excitons, strong optical coupling to low-mass quasiparticles with large de Broglie wavelength, and excellent control over the dipole properties and interactions .
Physical Review Letters, 2014
We report observation of oscillations in the dynamics of a microcavity polariton condensate forme... more We report observation of oscillations in the dynamics of a microcavity polariton condensate formed under pulsed nonresonant excitation. While oscillations in a condensate have always been attributed to Josephson mechanisms due to a chemical potential unbalance, here we show that under some localization conditions of the condensate, they may arise from relaxation oscillations, a pervasive classical dynamics that repeatedly provokes the sudden decay of a reservoir, shutting off relaxation as the reservoir is replenished. Using nonresonant excitation, it is thus possible to obtain condensate injection pulses with a record frequency of 0.1 THz.
Physical Review B, 2012
A polariton condensate transistor switch is realized through optical excitation of a microcavity ... more A polariton condensate transistor switch is realized through optical excitation of a microcavity ridge with two beams. The ballistically ejected polaritons from a condensate formed at the source are gated using the 20 times weaker second beam to switch on and off the flux of polaritons. In the absence of the gate beam the small builtin detuning creates potential landscape in which ejected polaritons are channelled toward the end of the ridge where they condense. The low loss photon-like propagation combined with strong nonlinearities associated with their excitonic component makes polariton based transistors particularly attractive for the implementation of all-optical integrated circuits. 71.36.+c Contemporary electronics face ever increasing obstacles in achieving higher speeds of operation. Down-scaling which has served Moore's law for decades is approaching the inherent limits of semiconductor materials . Even though a number of novel approaches have managed to improve operating frequency and power consumption, it is commonly acknowledged that in the future, charged carriers will have to be replaced by information carriers that do not suffer from scattering, capacitance and resistivity effects. Although photonic circuits have been proposed, a viable optical analogue to an electronic transistor has yet to be identified as switching and operating powers of these devices are typically high .