Tel: (+33) 1 69 63 60 54
Groupe: Elaboration et Physique des Structures Epitaxiées
, Groupe d'Optique des Structures Semi-conductrices
After completing a Dual Master's Degree between Supélec and the Georgia Institute of Technology specialized in micro- and optoelectronics (May 2009), I embarked upon a dual Ph.D. program between the Georgia Institute of Technology and the University of Lorraine. I obtained my Ph.D. in Materials Science from the University of Lorraine in January 2013, on the topic MOCVD growth and characterization of indium gallium nitride for photovoltaic applications. I then accepted a 2-year post-doctoral fellowship in electron microscopy in LPN, where I currently work under the supervision of Dr. Gilles Patriarche , while simultaneously completing my Ph.D. in Electrical and Computer Engineering from Georgia Tech.
Most of my current work revolves around the structural, mechanical, and electrical characterization of InP/Si wafer-fused interfaces. This work is carried out within the framework of ANR P2N project COHEDIO. The project investigates oxide-free wafer-bonding of InP to Si for advanced Photonic Integrated Circuits that fully integrate the mechanical, optical, thermal, and electrical properties of the two semiconductors.
A copy of my curriculum vitae can be found here, and a copy of my full list of publications here.
My current research interests evolve around the following topics:
- The quantification of the contrast in HAADF-STEM using EDX.
- Nano-mechanical characterization of hybrid III-V/Si interfaces combining STEM and instrumented nano-indentation.
- Characterization of the band alignment at and charge transport across III-V/Si hetero-interfaces obtained using direct oxide-free wafer bonding.
A brief description on these topics, as well as a few examples from recent publications and ongoing work are given below.
Quantification of the HAADF contrast using EDX
In high-angle annular dark-field (HAADF) STEM, the image intensity is proportional to the STEM specimen thickness, the density of the material being imaged and its composition. With careful specimen preparation and using a few EDX measurements to calibrate contrast variations, it is possible to reconstruct chemical mappings from HAADF-STEM images. These mappings combine the chemical precision of EDX and the resolution of HAADF-STEM, opening the path towards atomically-resolved, quantitative chemical mappings of samples observed in a STEM.
Fig.1. (a) HAADF-STEM image of an indium gallium nitride epilayer grown on GaN using MOVPE presenting nanometer-scale flucutations in the indium composition; (b) corresponding chemical mapping, quantifying the fluctuations of the indium composition. Results published in Nanotechnology ( link to article).
Such mappings can be correlated to other analytic transmission electron microscopy techniques, such cathodoluminescence in a STEM or dark-field electron holography, to help interpret optical or structural data obtained from these techniques.
Fig.2. (a) HAADF-STEM image of an InGaN/GaN sample; (b) corresponding chemical mapping; (c-f) energy-filtered emission spectra obtained from Cathodoluminescence in a STEM in the same region as in (a). Results currently under review for publication.
Additional applications sub-nanometrically resolved chemical mappings of Quantum Cascade Laser Structures or Nanowires that are useful for basic growth studies.
Fig.3. (a) HAADF-STEM image of an InGaAs/InAlAs THz QCL structure; (b) corresponding chemical mapping; (c) HAAF-STEM image of a GaAs nanowire with a AlGaAs wells as markers;(d) Corresponding chemical mapping.
Publications dans des journaux
- Sharpening the interfaces of axial heterostructures in self-catalyzed AlGaAs nanowires: experiment and theory
G. Priante, F. Glas, G. Patriarche, K. Pantzas, F. Oehler, J.-C. Harmand, Nano Lett. 16, 1917 (2016)
- Nondestructive three-dimensional imaging of crystal strain and rotations in an extended bonded semiconductor heterostructure
AI. Pateras, M. Allain, P. Godard, L. Largeau, G. Patriarche, A. Talneau, K. Pantzas, M. Burghammer, AA. Minkevich, V. Chamard, Phys. Rev. B 92, 205305 (2015)
- Bonding mechanism of a yttrium iron garnet film on Si without the use of an intermediate layer
K. Pantzas, G. Patriarche, A. Talneau, J. Ben Youssef, Appl. Phys. Lett. 105, 141601 (2014)
- Void-free direct bonding of InP to Si: Advantages of low H-content and ozone activation
A. Itawi, K. Pantzas, I. Sagnes, G. Patriarche, A. Talneau, J. Vac. Sci. Technol. B 32, 21201 (2014)
- Instrumented nanoindentation and scanning electron transmission microscopy applied to the study of the adhesion of InP membranes heteroepitaxially bonded to Si
K. Pantzas, E. Le Bourhis, G. Patriarche, A. Itawi, G. Beaudoin, I. Sagnes, A. Talneau, Eur. Phys. J.-Appl. Phys 65, 20702 (2014)
- Multilayered InGaN/GaN structure vs. single InGaN layer for solar cell applications: A comparative study
Y. El Gmili, G. Orsal, K. Pantzas, T. Moudakir, S. Sundaram, G. Patriarche, J. Hester, A. Ahaitouf, J.P. Salvestrini, A. Ougazzaden, Acta Materialia 61, 6587 (2013)
- Evaluation of the surface bonding energy of an InP membrane bonded oxide-free to Si using instrumented nanoindentation
K. Pantzas, G. Patriarche, E. Le Bourhis, D. Troadec, A. Itawi, G. Beaudoin, I. Sagnes, A. Talneau, Appl. Phys. Lett. 103, 81901 (2013)
- Suppression of crack generation in AlGaN/GaN distributed Bragg reflectors grown by MOVPE
T. Moudakir, S. Gautier, S. Suresh, M. Abid, Y. El Gmili, G. Patriarche, K. Pantzas, D. Troadec, J. Jacquet, F. Genty, PL. Voss, A. Ougazzaden, J. Cryst. Growth 370, 12 (2013)
- Semibulk InGaN: A novel approach for thick, single phase, epitaxial InGaN layers grown by MOVPE
K. Pantzas, Y. El Gmili, J. Dickerson, S. Gautier, L. Largeau, O. Mauguin, G. Patriarche, S. Suresh, T. Moudakir, C. Bishop, A. Ahaitouf, T. Rivera, C. Tanguy, PL. Voss, A. Ougazzaden, J. Cryst. Growth 370, 57 (2013)
- Structural and compositional characterization of MOVPE GaN thin films transferred from sapphire to glass substrates using chemical lift-off and room temperature direct wafer bonding and GaN wafer scale MOVPE growth on ZnO-buffered sapphire
S. Gautier, T. Moudakir, G. Patriarche, D. J. Rogers, V. E. Sandana, F. H. Teherani, P. Bove, Y. El Gmili, K. Pantzas, S. Sundaram, D. Troadec, PL. Voss, M. Razeghi, A. Ougazzaden, J. Cryst. Growth 370, 63 (2013)
- Comparison of Chemical and Laser Lift-off for the Transfer of InGaN-based p-i-n Junctions from Sapphire to Glass Substrates
K. Pantzas, G. Patriarche, 8626, 862611 (2013)
- Nanometer-scale, quantitative composition mappings of InGaN layers from a combination of scanning transmission electron microscopy and energy dispersive x-ray spectroscopy
K. Pantzas, G. Patriarche, D. Troadec, S. Gautier, T. Moudakir, S. Suresh, L. Largeau, O. Mauguin, PL. Voss, A. Ougazzaden, Nanotechnology 23, 455707 (2012)
- Mechanism of Ohmic Cr/Ni/Au contact formation on p-GaN
L. Magdenko, G. Patriarche, D. Troadec, O. Mauguin, E. Morvan, M.-A. di Forte-Poisson, K. Pantzas, A. Ougazzaden, A. Martinez, A. Ramdane, J. Vac. Sci. Technol. B 30, 22205 (2012)
- Distributed Bragg reflectors based on diluted boron-based BAlN alloys for deep ultraviolet optoelectronic applications
M. Abid, T. Moudakir, G. Orsal, S. Gautier, A. E. Naciri, Z. Djebbour, J.-H. Ryou, G. Patriarche, L. Largeau, H. J. Kim, Z. Lochner, K. Pantzas, D. Alamarguy, F. Jomard, R. D. Dupuis, J.P. Salvestrini, PL. Voss, A. Ougazzaden, Appl. Phys. Lett. 100, 51101 (2012)
- Investigation of a relaxation mechanism specific to InGaN for improved MOVPE growth of nitride solar cell materials
K. Pantzas, G. Patriarche, G. Orsal, S. Gautier, T. Moudakir, M. Abid, V. Gorge, Z. Djebbour, PL. Voss, A. Ougazzaden, Phys. Status Solidi A-Appl. Mat. 209, 25 (2012)
- Deep structural analysis of novel BGaN material layers grown by MOVPE
S. Gautier, G. Patriarche, T. Moudakir, M. Abid, G. Orsal, K. Pantzas, D. Troadec, A. Soltani, L. Largeau, O. Mauguin, A. Ougazzaden, J. Cryst. Growth 315, 288 (2010)