Abstract
We have studied the mechanisms of capture and intersubband relaxation in quantum wells by time resolved luminescence with subpicosecond resolution. The quantum mechanical capture time does not show strong oscillations due to the competing influence of different capture mechanisms. Intersubband relaxation is measured with times of the order of 1 ps, for well widths of the order of 100 Å.
The behaviour of quantum well based devices, and particularly of quantum well lasers or quantum well amplifiers, relies on the two dimensional character of the density of states. However, in most of these devices, active electrons and holes are injected by external contacts into the barrier layers. Therefore, correct operation of such devices rely on the precise mechanisms of capture and intersubband scattering. Time resolved techniques, and particularly luminescence, provide very interesting tools to get direct information on the times involved in such processes.
In quantum wells, capture mechanisms as well as intersubband scattering have not yet been fully characterized. Both of these should show a well defined variation as a function of the well thickness. In the case of capture, deep oscillations have been predicted when the well thickness is varied, as a result of the profound changes in the overlap of the wavefunctions of the states confined in the well and of those above the barriers 1. In the case of intersubband transitions, variation of the q vector of the emitted phonon changes the relaxation rate by one order of magnitude when the thickness of the well goes from 200 Å to 60Å 2. Furthermore, very large differences should be observed as soon as it is not any more possible to emit one LO phonon.
Luminescence allows quite easily to monitor the capture process as the barrier luminescence basically disappears as fast as the carriers are captured into the well. We show here that the capture time does not show the expected oscillations and we shall try to explain why.
Intersubband scattering is more difficult to monitor because of the necessary presence of holes to observe luminescence. We will show how the use of coupled quantum wells allows to overcome this difficulty. Strong differences are observed depending wether one optical phonon can be emitted or not.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
J.A. Brum, G. Bastard, Resonant carrier capture by semiconductor quantum wells, Phys. Rev., B33, 1420 (1985)
R. Ferreira, G. Bastard, Evaluation of some scattering times for electrons in unbiased and biased single and multiple quantum well structures, Phys. Rev., B40 1074 (1989)
J. Kervarec, M. Baudet, J. Caulet, P. Auvray, J.Y. Emery, A. Regreny, Some aspects of the x-ray structural characterization of GaA1As (n1) GaAs (n2)/GaAs (001) superlattices, J. Appl. Cryst. Growth, 17 196 (1984)
J. Shah, T.C. Damen, B. Deveaud, D. Block, Subpicosecond luminescence using sum frequency generation, Appl. Phys. Lett., 52 1886 (1987)
J. Shah, Ultrafast luminescence spectroscopy using sum-frequency generation, IEEE J. Quantum electron.,QE-24 276 (1988)
T. Damen, J. Shah, Femtosecond luminescence spectroscopy with 60 fs compressed pulses, Appl. Phys. Lett., 52 1291 (1988)
Day to day reproducibility is of the order of 100 fs due to the large aperture angle of the collecting objective.
H. Shichijo, R.M. Kolbas, N. Holonyak, Carrier collection in a semiconductor quantum well, Jr, Solid State Commun., 27 1029 (1978)
N. Holonyak, Jr, R.M. Kolbas, R.D. Dupuis, P.D. Dapkus, Quantum well heterostructure lasersIEEE J. Quantum Electron. QE-16 170 (1980)
J. Y, Tang, K. Hess, N. Holonyak, Jr, J.J. Coleman, P.D. Dapkus, The dynamics of electron-hole collection in quantum well heterostructures, J. Appl. Phys., 53 6043 (1982)
J. Christen, D. Bimberg, A. Steckenborn, G. Weimann, Localization induced electron-hole transition rate enhancement in GaAs Quantum wells, Appl. Phys. Lett., 44 84 (1984)
E.O. Göbel, H. Jung, J. Kuhl, K. Ploog, Recombination enhancement due to carrier localization in quantum well structures, Phys. Rev. Lett., 51 1588 (1983)
D. Bimberg, J. Christen, A. Steckenborn, G. Weimann, W. Schlapp., J. Lumin., 30 562 (1985)
Y.C. Lo, K.Y. Hsieh, R.M. Kolbas, Stimulated emission in ultrathin (20 Å) A1GaAsGaAs single quantum well heterostructures, Appl. Phys. Lett., 52 1853 (1988)
M.Babiker, B.K. Ridley, Effective mass eigenfunctions in superlattices and their role in well-capture, Superlatt. and Microstruct., 2 287 (1986)
M. Babiker, M.P. Chamberlain, A. Ghosal, B. Ridley, A new resonance phenomenon associated with electron transitions in superlattices and single quantum wells, Surf. Sci., 196 422 (1988)
M. Babiker, A. Ghosal, B. Ridley, Intrasubband transitions and well capture via confined, guided and interface LO phonons in superlattices, Superlatt. and Microstruct., 5 133 (1989)
J.A. Brum, G. Bastard, Direct and indirect carrier capture by semiconductor quantum wells, Superlatt. and Microstruct.,3 51 (1987)
J.A. Brum, T. Weil, J. Nagle, B. Vinter, Calculation of carrier capture time of a quantum well in graded-index separate-confinement heterostructures, Phys. Rev., B34 2381 (1986)
N. Ogasawara, A. Fujiwara, N. Ohgushi, S. Fukatsu, Y. Shiraki, Y. Katayama, R. Ito, Well-width dependence of photoluminescence excitation spectra in GaAs-AlGaAs quantum wells, Phys. Rev., B42 (1990)
J.Feldmann, G. Peter, E.O. Göbel, K. Leo, H.J. Polland, K. Ploog, K. Fujiwara, T. Nakayama, Carrier trapping in single quantum wells with different confinement structures, Appl.Phys. Lett., 51, 226 (1987)
H. Uchiki, T. Kobayashi, E. Tokunaga, Carrier diffusion and trapping by quantum wells, Phys. Stat. Solidi (b), 150 667 (1988)
D.J. Westland, D. Milailovic, J.F. Ryan, M.D. Scott, Optical time-of-flight measurement of carrier diffusion and trapping in an InGaAs/InP heterostructure, Appl. Phys. Lett., 51 590 (1987)
J. Kusano, Y. Segawa, T. Ayogi, S. Namba, H. Okamoto, Extremely slow relaxation of excitons in GaAs quantum wells, Phys. Rev., B40 1685 (1989)
H.J. Polland, K. Leo, K. Rother, K. Ploog, J. Feldmann, G. Peter, E.O. Gabel, K. Fujiwara, T. Nakayama, Y. Otha, Trapping of carriers in single quantum wells with different configurations of the confinement layers, Phys. Rev., B38 7635 (1988)
T.C. Damen, J. Shah, D.Y. Oberli, D.S. Chemla, J.E. Cunningham, J.M. Kuo, Dynamics of exciton formation and relaxation in GaAs quantum wells, Phys. Rev., B42 7434 (1990)
B. Deveaud, J. Shah, T.C. Damen, W.T. Tsang, Capture of electrons and holes in quantum wells, Appl. Phys. Lett., 52 1886 (1988)
R. Kersting, X.Q. Zhou, K. Wolter, D. Griinzmacher, H. Kurz, Subpicosecond luminescence study of carrier transfer in InGaAs/InP multiple quantum wells, Superlatt. and Microstruct., 7 345 (1990)
S. Morin, B. Deveaud, F. Clèrot, K. Fujiwara, K. Mitsunaga, Capture of photoexcited carriers in a single quantum well with different confinement structures, IEEE J. Quantum Electron., QE-27, 1669 (1991)
More precisely, this luminescence corresponds to transitions of electrons having an initial wave function with an energy larger than the conduction band offset.
D.Y. Oberli, D.R. Wake, M.V. Klein, J. Klem, T. Henderson, H. Morkoc, Timeresolved Raman scattering in GaAs Quantum wells, Phys. Rev. Lett., 59 696 (1987)
M.C. Tatham, J.F. Ryan, C.T. Foxon, Timeresolved Raman scattering measurement of electron-optical phonon intersubband relaxation in GaAs quantum wells, Phys. Rev. Lett., 63 1637 (1990)
A. Seilmeier, H-J. Hubner, G. Abstreiter, Intersubband relaxation in GaAs-A1GaAs quantum well structures observed directly by an infrared bleaching technique, Phys. Rev. Lett., 59 1345 (1987)
A. Seilmeier, This conference.
B. Deveaud, A. Chomette, F. Clérot, P. Auvray, A. Regreny, R. Ferreira, G. Bastard, Subpicosecond luminescence study of tunnelling and relaxation in coupled quantum wells, Phys. Rev., B 42 7021 (1990)
S. Gurvitz, I. Bar Joseph, B. Deveaud, Quantum tunnelling and relaxation in asymmetric coupled quantum wells, Phys. Rev.,B 43 14703 (1991)
K. Leo, J. Shah, J.P. Gordon, T.C. Damen, D.A.B. Miller, C.W. Tu, J.E. Cunningham, J.E. Henry, Effect of collisions and relaxation on coherent resonant tunnelling: hole tunnelling in GaAs/AlGaAs double quantum well structures, Phys Rev., B 42 7065 (1990)
See also for example: T. Weil, B. Vinter, Calculation of phonon assisted tunnelling between two quantum wells, J. Appl. Phys.,60 3227 (1986)
M. Nido, M.G.W. Alexander, W.W. Rühle, T. Schweitzer, K. Kölher, Nonresonant electron and hole tunneling times in GaAs/AlGaAs asymmetric double quantum wells, Appl. Phys. Lett., 56 355 (1990)
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1992 Springer Science+Business Media New York
About this chapter
Cite this chapter
Deveaud, B., Chomette, A., Clérot, F., Regreny, A. (1992). Subpicosecond Luminescence Study of Capture and Intersubband Relaxation in Quantum Wells. In: Rosencher, E., Vinter, B., Levine, B. (eds) Intersubband Transitions in Quantum Wells. NATO ASI Series, vol 288. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-3346-7_26
Download citation
DOI: https://doi.org/10.1007/978-1-4615-3346-7_26
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4613-6475-7
Online ISBN: 978-1-4615-3346-7
eBook Packages: Springer Book Archive