1,721,445 research outputs found
Spin dynamics in (110)-oriented quantum wells
No full textQuantum structures of III–V semiconductors grown on (1 1 0)-oriented substrates are promising for spintronic applications because they allow us to engineer and control spin dynamics of electrons. We summarise the theoretical ideas, which are the basis for this claim and review experiments to investigate them.<br/
Charge Buildup Effects In Asymmetric P-type Resonant Tunneling Diodes
No full textWe have investigated p-doped GaAs-AlAs resonant tunneling devices with asymmetric barriers under optical excitation. Transport and photoluminescence measurements were performed under identical bias conditions as a function of the light excitation intensity. We have observed the development of additional peaks, induced by illumination, between the main light- and heavy-hole resonances in the current-voltage characteristics (I(V)). We describe the behavior of these photo-induced peaks under a magnetic field parallel to the current. We propose that the observed properties are related to resonant tunneling of photoinduced electrons and associated excitonic effects. © 2005 Elsevier Ltd. All rights reserved.363-6356358Goldman, V.J., Tsui, D.C., Cunninghan, J.E., (1987) Phys. Rev. B, 35, p. 9387Leadbeater, M.L., Alves, E.S., Eaves, L., Henini, M., Hughes, O.H., Sheard, F.W., Toombs, G.A., (1988) Semicond. Sci. Technol., 3, p. 1060Wu, S.S., Chang, K.H., Lee, C.P., Chang, C.Y., Liu, D.G., Liou, C., (1991) Appl. Phys. Lett., 29, p. 87Skolnick, M.S., Hayes, D.G., Simmonds, P.E., Higgs, A.W., Smith, G.W., Hutchinson, H.J., Whitehouse, C.R., Halliday, D.P., (1990) Phys. Rev. B, 41, p. 10754Skolnick, M.S., Simmonds, P.E., Hayes, D.G., Higgs, A.W., Smith, G.W., Pitt, A.D., Whitehouse, C.R., Hughes, O.H., (1990) Phys. Rev. B, 42, p. 3069Young, J.F., Wood, B.M., Aers, G.C., Devine, R.L.S., Liu, H.C., Landheer, D., Buchanan, M., Mandeville, P., (1988) Phys. Rev. Lett., 60, p. 2085Tarucha, S., Ploog, K., (1988) Phys. Rev. B, 38, p. 4198Andrews, S.R., Tuberfield, A.J., Miller, B.A., (1993) Phys. Rev. B, 47, p. 15705Vodjdani, N., Chevoir, F., Thomas, D., Cote, D., Bois, P., Costard, E., Delaitre, S., (1989) Appl. Phys. Lett., 55, p. 1528Hayden, R.K., Eaves, L., Henini, M., Maude, D.K., Portal, J.C., Hill, G., (1992) Appl. Phys. Lett., 60, p. 1474Turner, T.S., Eaves, L., While, C.R.H., Henini, M., Hill, G., (1994) Semicond. Sci. Technol., 9, p. 552Buhmann, H., Wang, J., Mansouri, L., Beton, P.H., Eaves, L., Heath, M., Henini, M., (1994) Sol. Stat. Electr., 37, p. 973Cao, S.M., Willander, M., (1997) J. Appl. Phys., 81, p. 6221Sakai, J.-W., Fromhold, T.M., Beton, P.H., Eaves, L., Henini, M., Main, P.C., Sheard, F.W., Hill, G., (1993) Phys. Rev. B, 48, p. 5664Leadbeater, M.L., Alves, E.S., Eaves, L., Henini, M., Hughes, O.H., Celeste, A., Portal, J.S., Pate, M.A., (1989) Phys. Rev. B, 39, p. 343
Nonradiative exciton energy transfer in hybrid organic-inorganic heterostructures
No full textNonradiative energy transfer from a GaAs quantum well to a thin overlayer of an infrared organic semiconductor dye is unambiguously demonstrated. The dynamics of exciton transfer are studied in the time domain by using pump-probe spectroscopy at the donor site and fluorescence spectroscopy at the acceptor site. The effect is observed as simultaneous increase in the population decay rate at the donor and of the rise time of optical emission at the acceptor sites. The hybrid configuration under investigation provides an alternative nonradiative, noncontact pumping route to electrical carrier injection that overcomes the losses imposed by the associated low carrier mobility of organic emitters
Photocurrent enhancement in hybrid nanocrystal quantum-dot p-i-n photovoltaic devices
No full textWe fabricate a hybrid nanocrystal quantum-dot patterned p-i-n structure that utilizes nonradiative energy transfer from highly absorbing colloidal nanocrystal quantum dots to a patterned semiconductor slab to demonstrate a sixfold increase of the photocurrent conversion efficiency compared to the bare p-i-n semiconductor device.<br/
Effects Of Be Acceptors On The Spin Polarization Of Carriers In P-i-n Resonant Tunneling Diodes
Full text linkIn this paper, we have investigated the effect of Be acceptors on the electroluminescence and the spin polarization in GaAs/AlAs p-i-n resonant tunneling diodes. The quantum well emission comprise two main lines separated by ∼20meV attributed to excitonic and Be-related transitions, which intensities show remarkably abrupt variations at critical voltages, particularly at the electron resonant peak where it shows a high-frequency bistability. The circular-polarization degree of the quantum-well electroluminescence also shows strong and abrupt variations at the critical bias voltages and it attains relatively large values (of ∼-75% at 15T). These effects may be explored to design novel devices for spintronic applications such as a high-frequency spin-oscillators. © 2014 AIP Publishing LLC.1165Fabian, J., Matos-Abiague, A., Ertler, C., Stano, P., Zutic, I., (2007) Acta Phys. Slovaca, 57, p. 565. , 10.2478/v10155-010-0086-8Zutic, I., Fabian, J., Sarma, S.D., (2004) Rev. Mod. Phys., 76, p. 323. , 10.1103/RevModPhys.76.323Glazov, M.M., Alekseev, P.S., Adnoblyudov, O.M., Chistyakov, V.M., Tarasenko, S.A., Yassievich, I.N., (2005) Phys. Rev. B, 71, p. 155313. , 10.1103/PhysRevB.71.155313Slobodskyy, A., Gould, C., Slobodskyy, T., Becker, C.R., Schmidt, G., Molenkamp, L.W., (2003) Phys. Rev. Lett., 90, p. 246601. , 10.1103/PhysRevLett.90.246601Carvalho, H.B.D., Brasil, M.J.S.P., Lopez-Richard, V., Gobato, Y.G., Marques, G.E., Camps, I., Dacal, L.C.O., Hill, G., (2006) Phys. Rev. B, 74, p. 041305. , 10.1103/PhysRevB.74.041305Carvalho, H.B.D., Gobato, Y.G., Brasil, M.J.S.P., Lopez-Richard, V., Marques, G.E., Camps, I., Henini, M., Hill, G., (2006) Phys. Rev. B, 73, p. 155317. , 10.1103/PhysRevB.73.155317Carvalho, H.B.D., Brasil, M.J.S.P., Gobato, Y.G., Marques, G.E., Galeti, H.V.A., Henini, M., Hill, G., (2007) Appl. Phys. Lett., 90, p. 62120. , 10.1063/1.2472522Santos, L.F.D., Gobato, Y.G., Marques, G.E., Brasil, M.J.S.P., Henini, M., Airey, R., (2007) Appl. Phys. Lett., 91, p. 073520. , 10.1063/1.2772662Santos, L.F.D., Gobato, Y.G., Marques, G.E., Brasil, M.J.S.P., Henini, M., Airey, R., (2008) Appl. Phys. Lett., 92, p. 143505. , 10.1063/1.2908867Ruth, M., Gould, C., Molenkamp, L.W., (2011) Phys. Rev. B, 83, p. 155408. , 10.1103/PhysRevB.83.155408Ohya, S., Takata, K., Tanaka, M., (2011) Nat. Phys., 7, p. 342. , 10.1038/nphys1905Gobato, Y.G., Galeti, H.V.A., Santos, L.F.D., López-Richard, V., Cesar, D.F., Marques, G.E., Brasil, M.J.S.P., Airey, R.J., (2011) Appl. Phys. Lett., 99, p. 233507. , 10.1063/1.3668087Gordo, V.O., Herval, L.K.S., Galeti, H.V.A., Gobato, Y.G., Brasil, M.J.S.P., Marques, G.E., Henini, M., Airey, R.J., (2012) Nanoscale Res. Lett., 7, p. 592. , 10.1186/1556-276X-7-592Galeti, H.V.A., Bezerra, A.T., Gobato, Y.G., Brasil, M.J.S.P., Taylor, D., Henini, M., (2013) J. Phys. D, 46, p. 505313. , 10.1088/0022-3727/46/50/505313Galeti, H.V.A., Brasil, M.J.S.P., Gobato, Y.G., Henini, M., (2014) J. Phys. 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Nonlinear birefringence and time-resolved Kerr measurement of spin lifetimes in (110) GaAs/AlyGa1-yAs quantum wells
No full textWe report a study of the nonlinear birefringence in undoped (110)-oriented GaAs/AlGaAs quantum wells using time-resolved pump-probe Kerr spectroscopy. Due to the optical anisotropy of the (110) quantum well plane, photoexcited carriers can give rise to a nonlinear birefringence and so cause probe polarization rotation independent of the pump polarization, i.e., independent of spin orientation. We develop a methodology for accurate determination of electron-spin lifetimes using the Kerr technique which takes account of this phenomenon and present room-temperature measurements of wavelength and power density dependence of the spin-relaxation rate.<br/
Light Controlled Spin Polarization In Asymmetric N -type Resonant Tunneling Diode
Full text linkThe authors have observed a strong dependence of the circular polarization degree from the quantum well emission in an asymmetric n -type GaAsAlAsAlGaAs resonant tunneling diode on both the laser excitation intensity and the applied bias voltage. The sign of the circular polarization can be reversed by increasing the light excitation intensity when the structure is biased with voltages slightly larger than the first electron resonance. The variation of polarization is associated with a large density of photogenerated holes accumulated in the quantum well, which is enhanced due to the asymmetry of the structure. © 2007 American Institute of Physics.917Hanbicki, A., Van Erve, O.M.J., Magno, R., Kioseoglou, G., Li, C.H., Jonker, B.T., Itskos, G., Petrou, A., (2003) Appl. Phys. Lett., 82, p. 4092Jiang, X., Wang, R., Shelby, R.M., MacFarlane, R.M., Bank, S.R., Harris, J.S., Parkin, S.S.P., (2005) Phys. Rev. Lett., 94, p. 056601Motsnyi, V.F., Van Dorpe, P., Van Roy, W., Goovaerts, E., Safarov, V.I., Borghs, G., De Boeck, J., (2003) Phys. Rev. B, 68, p. 245319Fiederling, R., Keim, M., Reuscher, G., Ossau, W., Schmidt, G., Waag, A., Molenkamp, L.W., (1999) Nature (London), 402, p. 787Ohno, Y., Young, D.K., Beschoten, B., Matsukura, F., Ohno, H., Awschalom, D., (1999) Nature (London), 402, p. 790Oestreich, M.J., Hübner, M.J., Hägele, D., Klar, P.J., Heimbrodt, W., Rühle, W.W., Ashenford, D.E., Lunn, B., (1999) Appl. Phys. Lett., 74, p. 1251Jonker, B.T., Park, Y.D., Bennett, B.R., Cheong, H.D., Kioseoglou, G., Petrou, A., (2000) Phys. Rev. B, 62, p. 8180Braden, J.G., Parker, J.S., Xiong, P., Chun, S.H., Samarth, N., (2003) Phys. Rev. Lett., 91, p. 056602Mattana, R., George, J.-M., Jaffr̀s, H., Nguyen Van Dau, F., Fert, A., Ĺpine, B., Guivarc'H, A., J́źquel, G., (2003) Phys. Rev. Lett., 90, p. 166601Gruber, Th., Keim, M., Fiederling, R., Reuscher, G., Ossau, W., Schmidt, G., Molenkamp, M., Waag, A., (2001) Appl. Phys. Lett., 78, p. 1101Slobodskyy, A., Gould, C., Slobodskyy, T., Becker, C.R., Schmidt, G., Molenkamp, L.W., (2003) Phys. Rev. Lett., 90, p. 246601De Carvalho, H.B., Galvão Gobato, Y., Brasil, M.J.S.P., Lopez-Richard, V., Marques, G.E., Camps, I., Henini, M., Hill, G., (2006) Phys. Rev. B, 73, p. 155317De Carvalho, H.B., Brasil, M.J.S.P., Galvão Gobato, Y., Marques, G.E., Galeti, H.V.A., Henini, M., Hill, G., (2007) Appl. Phys. Lett., 90, p. 62120Buhmann, H., Mansouri, L., Wang, J., Beton, P.H., Mori, N., Eaves, L., Henini, M., Potemski, M., (1995) Phys. Rev. B, 51, p. 7969Teran, F.J., Eaves, L., Mansouri, L., Buhmann, H., Maude, D.K., Potemski, M., Henini, M., Hill, G., (2005) Phys. Rev. B, 71, p. 161309Glasberg, S., Finkelstein, G., Shtrikman, H., Bar-Joseph, I., (1999) Phys. Rev. B, 59, p. 10425Vanhoucke, T., Hayne, M., Henini, M., Moshchalkov, V.V., (2002) Phys. Rev. B, 65, p. 041307Marie, X., Amand, T., Le Jeune, P., Paillard, M., Renucci, P., Golub, L.E., Dymnikov, V.D., Ivchenko, E.L., (1999) Phys. Rev. B, 60, p. 5811Van Kesteren, H.W., Cosman, E.C., Van Der Poel, W.A.J.A., Foxon, C.T., (1990) Phys. Rev. B, 41, p. 528
Optical control of spins in semiconductors
No full textRecent and ongoing optical experiments on mechanisms and methods for control and gating of spin relaxation in semiconductor quantum wells are reviewed. We discuss work on high-mobility two-dimensional electron gases in (001)-grown GaAs/AlGaAs wells which reveals two new aspects of D'yakonov, Perel' and Kachorovskii (DPK) spin dynamics, namely oscillatory spin evolution in a quasi-collision-free regime at low temperatures and strong deviation from the standard expectation that spin-relaxation rate will be proportional to electron mobility at higher temperatures. The latter may indicate that electron–electron scattering, neglected hitherto, is important for spin relaxation. Experiments on (011)-grown GaAs/AlGaAs quantum wells confirm that this orientation leads to extension of electron spin memory by as much as two orders of magnitude at room temperature due to suppression of the major contribution to DPK spin relaxation. Results for a sample with built-in electric field give a strong indication that, for this growth orientation, room temperature spin memory may be gated by external applied voltage
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