Modulation Spectroscopy Laboratory
Research
research coordinator: Mario Geddo
OPTICAL PROPERTIES OF QUANTUM CONFINED III-V SEMICONDUCTOR SYSTEMS. To date the research activity carried on at the modulation spectroscopy laboratory is mainly focused on the study of the optical properties of bulk and quantum confined III-V semiconductor systems. Particular efforts are directed to the study of quantum dot nanostructures for fiber optic communications and to the investigation of the astonishing properties of dilute nitrides in view of their possible applications in the fields of optoelectronics and telecommunications. This line of research is directed to the study of the optical properties of GaAs based quantum dot (QD) nanostuctures by using modulation spectroscopy techniques, spectroscopic Ellipsometry and Raman scattering. The goal is to optimize the QDs emission efficiency at 1.31, 1.55, 0.98 micron (i.e. the spectral windows of specific interest for fiber optic communications). The investigated nanostructures consist of InAs self-assembled QDs grown by MBE on GaAs, InGaAs and AlGaAs buffer layers.
Participants: M. Geddo, G. Guizzetti, M. Patrini, E. Giulotto Collaborations: Dipartimento di Fisica, Università di Roma “ La Sapienza”;
Dipartimento di Fisica, Università di Parma;
CNR-IMEM, Parma. Projects: CNR-MADESS II (2001-2003) “Fisica e tecnologia dei dispositivi compositi”;
FIRB (2004-2007) “Nanotecnologie e nanodispositivi per la Società dell’Informazione”. PhD theses: R. Pezzuto, Studio mediante fotoriflettanza delle proprietà ottiche di eterostrutture basate su GaAs per emissione a 1.3 micron. (Università di Pavia, 2002)
Key publications: Photoreflectance characterization of InAs/GaAs self-assembled quantum dots grown by ALMBE Optical study of the strain driven tuning of the emission energy in InAs/InGaAs quantum-dot nanostructures Metamorphic buffers and optical measurement of residual strain Quantum dot strain engineering of InAs/InGaAs nanostructures The role of wetting layer states on the emission efficiency of InAs/InGaAs metamorphic quantum dot nanostructures Raman scattering in InAs/AlGaAS quantum dots nanostrustures This line of research is directed to the study of the optical properties of dilute nitrides by using static and modulated reflectance techniques, Spectroscopic Ellipsometry, Raman scattering and AFM. The goal is to highlight the peculiar intriguing structural and electronic properties of these materials, taking into account their promising applicatinons in the field of optoelectronic and telecommunications.
Participants: M. Geddo, G. Guizzetti, M. Patrini, M. Galli Collaborations: Dipartimento di Fisica, Università di Roma “ La Sapienza”;
CNR-TASC, Trieste. Projects: CNR-MADESS II (2001-2003) “Fisica e tecnologia dei dispositivi compositi”;
FIRB (2004-2007) “Nanotecnologie e nanodispositivi per la Società dell’Informazione”. PhD theses: T. Ciabattoni, Studio e caratterizzazione ottica di nanostrutture di semiconduttori III-V. (Università di Pavia, 2007)
Key publications: Effect of temperature on the optical properties of (InGa)(AsN)/GaAs single quantum wells Effect of nitrogen on the temperature dependence of the energy gap in
In(x)Ga(1-x)As(1-y)N(y)/GaAs single quantum wells
Photoreflectance evidence of the N-induced increase of the exciton binding energy in an (InGa)(AsN) alloy Photoreflectance and Reflectance investigation of deuterium-irradiated GaAsN Optical study of hydrogen-irradiated GaAsN/GaAs heterostructures An all Optical mapping of the strain field in GaAsN/GaAsN:H wires
M. Geddo, R. Ferrini, G. Guizzetti, M. Patrini, S. Franchi, P. Frigeri,G. Salviati and L. Lazzarini
Eur. Phys. J. B 16, 19 (2000)
M. Geddo, V. Bellani, G. Guizzetti, M. Patrini, T. Ciabattoni, L. Seravalli, M. Minelli, P. Frigeri and S. Franchi
The Electrochemical Society Proc. Vol. 2004-13 p. 373 (2005)
M. Geddo, G. Guizzetti, M. Patrini, T. Ciabattoni, L. Seravalli, P. Frigeri and S. Franchi
Appl. Phys. Lett. 87, 263120 (2005)
L. Seravalli, M. Minelli, P. Frigeri, S. Franchi, G. Guizzetti, M. Patrini, T. Ciabattoni and M. Geddo
Journal of Appl. Phys.101, 024313 (2007)
L. Seravalli, G. Trevisi1, P. Frigeri, S. Franchi, M. Geddo and G. Guizzetti
Nanotechnology 20, 275703 (2009)
E. Giulotto, M. Geddo, M. S. Grandi, G. Guizzetti, L. Seravalli, P. Frigeri and S. Franchi
Appl. Phys. Lett. 98, 111903 (2011)
A. Polimeni, M. Capizzi, M. Geddo, M. Fisher, M. Reinhardt and A.Forchel
Appl. Phys. Lett. 77, 2870 (2000)
A. Polimeni, M. Capizzi, M. Geddo, M. Fisher, M. Reinhardt and A.Forchel
Phys. Rev. B 63, 195320 (2001)
M. Geddo, G. Guizzetti, M. Capizzi, A. Polimeni, D. Gollub and A. Forchel
Appl. Phys. Lett. 83, 470 (2003)
M. Geddo, T. Ciabattoni, G. Guizzetti, M. Galli, M. Patrini, A. Polimeni, R. Trotta, M. Capizzi, G. Bais, M. Piccin, S. Rubini, F. Martelli and A. Franciosi
Appl. Phys. Lett. 90, 091907 (2007)
M. Geddo, M. Patrini, G. Guizzetti, M. Galli, R. Trotta, A. Polimeni, M. Capizzi, M. Martelli and S. Rubini
Journal of Appl. Phys. 109, 123511 (2011)
M. Geddo, E. Giulotto, M. S. Grandi, M. Patrini, R. Trotta, A. Polimeni, M. Capizzi, M. Martelli and S. Rubini
Appl. Phys. Lett. 101, 191908 (2012)