ABSTRACT We report systematic temperature-dependent measurements of photoluminescence spectra in self-assembled InGaAs/GaAs quantum rings (QRs) under resonant excitation condition. We have studied the rise in temperature of the ground-state intensity. The carrier transfer between the ground state of the small ring family towards the big-ring family of the bimodal size distribution is identified by analyzing the photoluminescence spectra. This effect is observed in very thin spacer and under resonant excitation. This situation makes important the lateral tunneling of excitons between rings under low temperatures (10 K). Tunneling time about 1ns was estimated at low temperature and compared to similar carrier transfer in quantum dots (QDs) found in the literature.
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nullR. Naouari, W. Ouerghui, J. Martinez-Pastor, M. Maaref, D. Granados and J. Garcia, "Exciton Dynamics in Stacked InGaAs/GaAs Quantum Rings Under Resonant Excitation," Journal of Modern Physics, Vol. 2 No. 7, 2011, pp. 714-718. doi: 10.4236/jmp.2011.27083.
 S. Sanguinetti, M. Henini, M. Grassi Alessi, M.Capizzi, P. Frigeri, and S. Franchi, “Carrier thermal escape and retrapping in self-assembled quantum dots, ” Phys. Rev. B, Vol. 60, No. 11, 1999, pp. 8276- 8283.
 J.W. Tomm, T. Elsaesser, Yu. I. Mazur, H. Kissel, G.G. Tarasov, Z.Ya. Zhuchenko, W.T. Masselink, ‘‘ Transient luminescence of dense InAs/GaAs quantum dot arrays,” Phys. Rev. B, Vol. 67, No. 4, 2003, pp. 045326-045333.
 W. Ouerghui , J. Martinez-Pastor , J. Gomis , A. Melliti , M.A. Maaref, D. Granados and J. M Garcia, ‘‘Effect of carrier transfer on the PL intesity in self-assembled InGaAs/GaAs quantum rings,” Eur. Phys. J. Appl. Phys, Vol. 35, No. 3, 2006, pp. 159-163.
 F. Suarez, D. Granados, M.L. Dotor and J. M. Garcia, ‘‘Laser devices with stacked layers of InGaAs/GaAs quantum rings,”Nanothechnology, Vol. 15, No. 4, 2004, pp.126-130.
 Yu. I. Mazur, X. Wang, Z. M. Wang, G. J. Salamo, M. Xiao, H. Kissel, ‘‘Photoluminescence study of carrier transfer among vertically aligned double-stacked InAs/GaAs quantum dot layers,”Appl. Phys. Lett, Vol. 81, No. 13, 2002, pp. 2469-2471.
 W. Ouerghui, J. Martinez-Pastor, J. Gomis, M.A. Maaref, D. Granados, and J. M. Garcia, ‘‘Lateral tunneling in stacked InGaAs/ GaAs quantum rings,” Eur. Phys. J. B, Vol. 54, No. 2, 2006, pp. 217-223.
 M. L. Dotor, M.Recio, D. Golmayo and F. Briones, ‘‘Photoluminescence characterization of GaAs quantum well laser structure with AlAs/GaAs superlattices wave guide,” J. Appl. Phys, Vol. 72, No. 12, 1992, pp. 5861-5866.
 D. Granados, J. M. García, T. Ben and S. I. Molina, ‘‘Vertical order in stacked layers of self-assembled quantum rings on GaAs (001),” Appl. Phys. Lett, Vol. 86, No.7, 2005, pp. 071918-071920.
 P. Offermans, P. M. Koenraad, J. H. Wolter, D. Granados, J. M. García, V. M. Fomin, V. M. Gladilin, and J. T. Devreese, ‘‘Atomic-scale of self-assembled InGaAs quantum rings in GaAs,” Appl. Phys. Lett, Vol. 87, No. 13, 2005, pp. 131902-131904.
 S. Taddei, M. Collocci, A. Vinattieri, P. G. Gucciardi, F. Bogani, S. Franchi, P. Frigeri, L. Lazzarini, and G. Salviati, ‘‘Vertical coupling effect in arrays of InAs quantum dots,” Phys. Stat. Solidi A, Vol. 224, No. 2, 2001, pp. 413-417.
 S. Taddei, M. Collocci, A. Vinattieri, F. Bogani, S. Franchi, P. Frigeri, L. Lazzarini, and G. Salviati, ‘‘Vetical coupling and transitions energies in multilayer InAs/GaAs quantum-dot structures,” Phys. Rev. B. Vol 62, No. 15, 2000, pp. 10220-10225.
 W. Jaskolski, M. Zielinski, G.W. Bryant, ‘‘Coupling and strain effects in vertically stacked double InAs/ GaAs quantum dots,” Acta Physica Polonica A, Vol. 106, No.2, 2004, pp. 193-205.
 A.Takeuchi, T. Kuroda, K. Mase, Y. Nakata and N. Yokoyama, ‘‘Dynamics of carrier tunneling between vertically aligned double quantum dots,” Phys. Rev B. Vol. 62, No. 3, 2000, pp. 1568-1571.
 T. Nakaoka, J. Tatebayashi, Y. Arakawa, T. Saito, ‘‘Carrier relaxation in closely stacked InAs quantum dots: Tight-Binding approach,” J. Appl. Phys.Vol. 96, No. 1, 2004, pp.150-154.
 R. Heitz, I.Mukhametzhanov, P. Chen. And A. Madhucar, ‘‘Exciton transfer in self-orgonized asymetric quantum dot pairs,” Phys. Rev. B, Vol.58, No. 16, 1988, pp.10151-10154.