Circular polarization in n-type resonant tunneling diodes with Si delta-doping in the quantum well

In this work, we have investigated magneto-transport and polarization resolved photoluminescence of a GaAs/AlGaAs resonant tunneling diode with Si delta-doping at the center of the quantum well under a magnetic field parallel to the tunnel current. Three resonant peaks were observed in the current-voltage characteristics curve (J(V)) which were associated to donor-assisted resonant tunneling, electron resonant tunneling and to phonon-­assisted resonant tunneling. The optical emission from GaAs contact layers shows evidence of highly spin-polarized two-dimensional electron and hole gases which affect the spin-polarization of carriers in the well. The quantum well photoluminescence shows strong circular polarization degrees with values up to 85% under 15T at the donor assisted resonant tunneling peak voltage. Our results can be exploited for future development of voltage-controlled spintronics devices

Experimental evidences of quantum confined 2D indirect excitons in single barrier GaAs/AlAs/GaAs heterostructure using photocapacitance at room temperature

We investigated excitonic absorptions in a GaAs/AlAs/GaAs single barrier heterostructure using both photocapacitance and photocurrent spectroscopies at room temperature. Photocapacitance spectra show well defined resonance peaks of indirect excitons formed around the C-AlAs barrier. Unlike DC-photocurrent spectra, frequency dependent photocapacitance spectra interestingly red shift, sharpen up, and then decrease with increasing tunneling at higher biases. Such dissimilarities clearly point out that different exciton dynamics govern these two spectral measurements. We also argue why such quantum confined dipoles of indirect excitons can have thermodynamically finite probabilities to survive even at room temperature. Finally, our observations demonstrate that the photocapacitance technique, which was seldom used to detect excitons in the past, is useful for selective detection and experimental tuning of relatively small numbers ( 1011/cm2) of photo-generated indirect excitons having large effective dipole moments in this type of quasi-two dimensional heterostructures

Effects Of Be Acceptors On The Spin Polarization Of Carriers In P-i-n Resonant Tunneling Diodes

In 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. D., 47, p. 165102. , 10.1088/0022-3727/47/16/165102Evans, H.B., Eaves, L., Henini, M., (1994) Semicond. Sci. Technol., 9, p. 555. , 10.1088/0268-1242/9/5S/042Holtz, P.O., Sundaram, M., Merz, J.L., Gossard, A.C., (1989) Phys. Rev. B, 40, p. 10021. , 10.1103/PhysRevB.40.10021Potemski, M., Maan, J.C., Fasolino, A., Ploog, K., Weimann, G., (1990) Surf. Sci., 229, p. 151. , 10.1016/0039-6028(90)90857-5Godlewskiy, M., Holtzz, P.O., Bergmanz, J.P., Monemarz, B., Reginskix, K., Bugajskix, M., Goldysk, E.M., Tansley, T.L., (1997) Semicond. Sci. Technol., 12, pp. 1416-1421. , 10.1088/0268-1242/12/11/014Harris, C.I., Monemar, B., Kalt, H., Holtz, P.O., Sundaram, M., Merz, J.L., Gossard, A.C., (1994) Phys. Rev. B, 50, p. 18367. , 10.1103/PhysRevB.50.18367Kundrotas, J., Erškus, A., Valušis, G., Li, L.H., Linfield, E.H., Johannessen, A., Johannessen, E., (2012) J. Appl. Phys., 112, p. 043105. , 10.1063/1.4745893Holtz, P.O., Zao, Q.X., (2004) Impurities Confined in Quantum Structures, , (Springer)Wojcik, P., Adamowski, J., Woloszyn, M., Spisak, B.J., (2012) Phys. Rev. B, 86, p. 165318. , 10.1103/PhysRevB.86.165318Goldman, V.J., Tsui, D.C., Cunningham, J.E., (1987) Phys. Rev. Lett., 58, p. 1256. , 10.1103/PhysRevLett.58.1256Gobato, Y.G., Berroir, J.M., Guldner, Y., Vieren, J.P., Chevoir, F., Vinter, B., (1991) Phys. Rev. B, 44, p. 13795. , 10.1103/PhysRevB.44.13795Miller, R.C., Gossard, A.C., Tsang, T., Munteanu, O., (1982) Phys. Rev. B, 25, p. 3871. , 10.1103/PhysRevB.25.3871Boffety, D., Vasson, A., Vasson, A.-M., Leymarie, J., Cheng, T.S., Bates, C.A., Chamberlain, J.M., (1996) Semicond. Sci. Technol., 11, p. 340. , 10.1088/0268-1242/11/3/011Zheng, W.M., Halsall, M.P., Harmer, P., Harrison, P., Steer, M.J., (2002) J. Appl. Phys., 92, p. 6039. , 10.1063/1.1516872Greene, L., Bajaj, K.K., Phelps, D.E., (1984) Phys. Rev. B, 29, p. 1807. , 10.1103/PhysRevB.29.1807Oelgart, G., Proctor, M., Martin, D., Morier-Genaud, F., Reinhart, F.-K., Orschel, B., Andreani, L.C., Rhan, H., (1994) Phys. Rev. B, 49, p. 10456. , 10.1103/PhysRevB.49.10456Galeti, H.V.A., (2012) Semicond. Sci. Technol., 27, p. 015018. , 10.1088/0268-1242/27/1/01501

Light Controlled Spin Polarization In Asymmetric N -type Resonant Tunneling Diode

The 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

Photophysics of poly(p-phenylene vinylene) films

We report on time resolved photoluminescence (PLRT) measurements in poly(p-phenylene vinylene) (PPV) films irradiated by laser in the presence of air. We observe a PL intensity enhancement and a biexponential decay dynamics of PL signal for all irradiated films. These results can be understood in terms of a chain shortening process due to carbonyl incorporation and formation of an energy profile that extends and migrates into the film and enables efficient spectral diffusion of excited carriers to a non-degraded PPV segments by Förster energy transfer

Polarization Resolved Luminescence In Asymmetric N -type Gaasalgaas Resonant Tunneling Diodes

We have investigated the polarized emission from a n -type GaAsAlGaAs resonant tunneling diode under magnetic field. The GaAs contact layer emission shows a large constant negative circular polarization. A similar result is observed for the quantum well, but only when electrons are injected from the substrate, while for inverted biases, the polarization tends to become positive for small voltages and large laser excitation intensities. We believe that the quantum well polarization may be associated to the partial thermalization of minority carriers on the well subbands and is thus critically dependent on the bias-controlled density of carriers accumulated in the well. © 2008 American Institute of Physics.9214Hanbicki, 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, T., 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. 062120Dos Santos, L.F., Galvão Gobato, Y., Marques, G.E., Brasil, M.J.S.P., Henini, M., Airey, R., (2007) Appl. Phys. Lett., 91, p. 073520Snelling, M.J., Blackwood, E., MacDonagh, C.J., Harley, R.T., Foxon, C.T.B., (1992) Phys. Rev. B, 45, p. 392

Structural And Optical Properties Of n-Type and p-Type GaAs(1−x)Bix Thin Films Grown By Molecular Beam Epitaxy On (311)B GaAs Substrates

In this paper, we report on the structural and optical properties of n-type Si-doped and p-type Be-doped GaAs(1−x)Bix thin films grown by molecular beam epitaxy on (311)B GaAs substrates with nominal Bi content x=5.4%. Similar samples without Bi were also grown for comparison purposes (n-type GaAs and p-type GaAs). X-ray diffraction, micro-Raman at room temperature, and photoluminescence (PL) measurements as a function of temperature and laser excitation power (PEXC) were performed to investigate their structural and optical properties. X-ray diffraction results revealed that the Bi incorporation in both n-type and p-type doped GaAsBi was similar, despite that the samples present remarkable differences in the number of Bi related defects, non-radiative centers and alloy disorder. Particularly, our results evidence that the Bi-related defects in n- and p-doped GaAsBi alloys have important impact on the differences of their optical properties

Photon-assisted Tunnelling Studies In Double Barrier Structures

We have measured I(V) characteristics and photoluminescence spectra of a double barrier diode with roughness interface and island formation in the quantum well under high photoexcitation intensity. We have observed a reduction of the resonant peak, peak to valley ratio and bistability region in the I(V) characteristics due to the change of electronic charge stored in the well induced by photon absorption and emission process. The photoluminescence spectra under high photoexcitation intensity are measured as a function of applied bias and temperature. A saturation effect is observed for the lowest energy peak which reduces the transfer of carriers between islands in the tunnelling process.274256259Skolnick, 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., 42, p. 3069Skolnick, M.S., Hayes, D.G., Simmonds, P.E., Higgs, A.W., Smith, G.W., Huchinson, H.J., Whitehouse, C.R., Halliday, D.P., (1990) Phys. Rev., 41, p. 10754Wang, T.H., Mei, X.B., Jiang, C., Uang, Y., Zhou, J.M., Yang, G.Z., (1993) Appl. Phys. Lett., 62, p. 1149Bertram, D., Grahn, H.T., Van Hoof, C., Genoe, J., Borghs, G., Ruble, W.W., Von Klitzing, K., (1994) Phys. Rev. B, 50, p. 17309Buhmann, H., Mansouri, L., Wang, J., Beton, P.H., Mori, N., Eaves, L., Henini, M., Potemski, M., (1995) Phys. Rev. B, 51, p. 7969Yan, Z.C., Goovaerts, E., VanHoof, C., Bouwen, A., Borghs, G., (1995) Phys. Rev. B, 52, p. 5907Galvão Gobato, Y., Triques, A.L.C., Schulz, P.A., (1997) 7BWSP, , also submitedInarrea, J., Platero, G., (1996) Europhys. Lett., 33, p. 47

Interface Roughness Effects In Resonant Tunneling Structures

We have measured I(V) characteristics and photoluminescence spectra of GaAs/In0.1Ga0.9As/AlAs double harrier diode with interface roughness and island formation in the quantum well (QW). Typical QW photolummescence (PL) and photoluminescence excitation (PLE) spectra present a splitting for the fundamental transition due to island formation in the QW. The position, intensity and linewidth of these lines are investigated as a function of applied bias photoexcitation intensity and temperature.1641137140Dietze, W.T., Darling, B., (1996) Phys. Rev. B, 53, p. 3925Skolnick, 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., 42, p. 3069Skolnick, M.S., Hayes, D.G., Simmonds, P.E., Higgs, A.W., Smith, G.W., Huchinson, H.J., Whitehouse, C.R., Halliday, D.P., (1990) Phys. Rev., 41, p. 10754Wang, T.H., Mei, X.B., Jiang, C., Uang, Y., Zhou, J.M., Yang, G.Z., (1993) Appl. Phys. Lett., 62, p. 1149Klann, R., Grahn, T., Fujiwara, F., (1995) Phys. Rev. B, 51, p. 10232Inarrea, J., Platero, G., (1996) Europhys. Lett., 33, p. 47

Interface Roughness Studies In Double Barrier Structures

Photoluminescence spectroscopy is used to investigate tunneling of electrons and holes through GaAs/In)0.11Ga0.9As/AlAs double barrier tunneling structure with interface roughness. Typical quantum well photoluminescence spectra present a splitting atributed to interface roughness effects, namely growth island formation in the quantum well. The position, intensity and linewidth of these lines are investigated as function of applied bias and temperature. The integrated photoluminescence intensity and linewidth of both lines are correlated to tunnel current bias in the low photoexcitation intensity. A transfer of carrier between these islands is observed at the begining of resonant tunneling regime. Finally, the states of these islands are selectively populated by electrons and holes with applied bias.274244247Skolnick, 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., 42, p. 3069Skolnick, M.S., Hayes, D.G., Simmonds, P.E., Higgs, A.W., Smith, G.W., Huchinson, H.J., Whitehouse, C.R., Halliday, D.P., (1990) Phys. Rev., 41, p. 10754Wang, T.H., Mei, X.B., Jiang, C., Uang, Y., Zhou, J.M., Yang, G.Z., (1993) Appl. Phys. Lett., 62, p. 1149Bertram, D., Grahn, H.T., Van Hoof, C., Genoe, J., Borghs, G., Ruhle, W.W., Von Klitzing, K., (1994) Phys. Rev. B, 50, p. 17309Buhmann, H., Mansouri, L., Wang, J., Beton, P.H., Mori, N., Eaves, L., Henini, M., Potemski, M., (1995) Phys. Rev., B51, p. 7969Yan, Z.C., Goovaerts, E., VanHoof, C., Bouwen, A., Borghs, G., (1995) Phys. Rev. B, 52, p. 5907Klann, R., Grahn, T., Fujiwara, F., (1995) Phys. Rev. B, 51, p. 10232Dietze, W.T., Darling, B., (1996) Phys. Rev. B, 53, p. 392