Time constant for relaxation of n=2 excitons into n=1 continuum states in GaAs quantum wells

Pal, Bipul; Vengurlekar, A. S.
July 2001
Applied Physics Letters;7/2/2001, Vol. 79 Issue 1, p72
Academic Journal
We resonantly excite excitons associated with the second electron and heavy hole subbands (n=2 excitons) in 13 and 17.5 nm GaAs quantum wells (QWs) at 8 K to perform femtosecond degenerate four wave mixing measurements. We deduce the lifetime T[sub 1] of the n=2 excitons to be approx. 890 fs and approx. 2.63 ps, respectively, for the 13 and 17.5 nm QWs. © 2001 American Institute of Physics.


Related Articles

  • Photoabsorption due to excitons for InGaAs-GaAs superlattice quantum wells in the presence of an applied electric field. Coffey, D. // Journal of Applied Physics;5/1/1988, Vol. 63 Issue 9, p4626 

    Focuses on the calculation of the absorption at the band-gap edge due to excitons in gallium arsenide-gallium arsenide superlattice quantum wells. Reason quantum wells are formed; Effect of the applied electric field parallel to the direction in which electrons and holes are confined;...

  • Carrier transport and recombination in resonantly excited InGaAs/GaAs MQWs. Aleksiejunas, Ramunas; Kadys, Arunas; Jarasiunas, Kestutis; Saas, Florian; Griebner, Uwe; Tomm, Jens W. // AIP Conference Proceedings;2007, Vol. 893 Issue 1, p461 

    We present nonlinear optical studies of the non-equilibrium carrier dynamics in InGaAs/GaAs quantum well structures. We exploit the free-carrier and electron spin-governed nonlinearities in pump-probe and four-wave mixing experiments to measure the carrier lifetime, spin relaxation time, and...

  • Excitonic electroabsorption in extremely shallow quantum wells. Goossen, K. W.; Cunningham, J. E.; Jan, W. Y. // Applied Physics Letters;12/10/1990, Vol. 57 Issue 24, p2582 

    We report the remarkable observation of strong room-temperature excitonic features in the absorption spectra of GaAs-AlxGa1-xAs quantum wells (QWs) for values of x as low as 0.02. This has important implications for high-power modulators, since saturation intensities have been shown to be higher...

  • Evidence of room-temperature exciton by magnetophotoreflectance in epitaxial GaAs and quantum well structures. Zheng, X. L.; Heiman, D.; Lax, B.; Chambers, F. A.; Stair, K. A. // Applied Physics Letters;3/21/1988, Vol. 52 Issue 12, p984 

    Photoreflectance experiments with magnetic fields up to 14.5 T are performed on epitaxial GaAs and GaAs/Ga1-xAlxAs quantum well samples at room temperature and 2 K. Our experiments show unique and direct evidence that photoreflectance structures are excitonic transitions in all of the above cases.

  • Effect of free electron-hole pairs on the saturation of excitonic absorption in GaAs/AlGaAs quantum wells. Litvinenko, K. L.; Lysenko, V. G.; Hvam, I. M. // Physics of the Solid State;Jun98, Vol. 40 Issue 6, p1032 

    The pump-probe experimental method is used to investigate the effect of photoexcited carriers on the dynamics of the exciton absorption spectra of GaAs / Al[sub x]Ga[sub 1 - x]As-multilayer quantum wells. Use of the method of moment analysis for processing the results makes it possible to...

  • Transport properties of excitons in GaAs quantum wells-time-resolved Raman probe. Tsen, K. T.; Sankey, O. F.; Morkoç, H. // Applied Physics Letters;10/15/1990, Vol. 57 Issue 16, p1666 

    Time-resolved, space-imaged Raman spectroscopy has been employed to study the transport properties of excitons in GaAs quantum wells. For an injected exciton density of nex [bar_over_tilde:_approx._equal_to]1.5×1011 cm-2, the experimental results show that exciton transport can be well...

  • Evidence for excitonic decay of excess charge carriers in high quality GaAs quantum wells at room temperature. Bimberg, D.; Christen, J.; Werner, A.; Kunst, M.; Weimann, G.; Schlapp, W. // Applied Physics Letters;7/14/1986, Vol. 49 Issue 2, p76 

    A comparative study is presented of the room-temperature decay of laser excited microwave photoconductivity and of cathodoluminescence of high quality GaAs multiple quantum wells grown by molecular beam expitaxy and of high quality GaAs liquid phase epitaxial layers. The results from both...

  • Enhancement in excitonic absorption due to overlap in heavy-hole and light-hole excitons in GaAs/InAlGaAs quantum well structures. Kothiyal, G. P.; Hong, S.; Debbar, N.; Bhattacharya, P. K.; Singh, J. // Applied Physics Letters;10/5/1987, Vol. 51 Issue 14, p1091 

    In this letter we present experimental and theoretical results for excitonic transitions in coherently strained GaAs/InGaAlAs multiquantum well structures grown on a GaAs substrate. Absorption spectra of the structure with the substrate removed show an extremely sharp exciton peak with an...

  • Two-wavelength optical switching in a GaAs multiple quantum well directional coupler. Cada, M.; Keyworth, B. P.; Glinski, J. M.; Rolland, C.; SpringThorpe, A. J.; Miner, C. J.; Hill, K. O. // Applied Physics Letters;5/21/1990, Vol. 56 Issue 21, p2080 

    Preliminary experimental results are reported on two-wavelength switching in a GaAs-based multiple quantum well planar directional coupler. It is verified that a novel design of the multiple quantum well (MQW) coupling region leads to a wavelength multiplexing/demultiplexing/switching operation....


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics