Effects Of A Nearby Mn Delta Layer On The Optical Properties Of An Ingaas/gaas Quantum Well

We investigated the effects of nearby Mn ions on the confined states of a InGaAs/GaAs quantum well through circularly polarized and magneto-optical measurements. The addition of a Mn delta-doping layer at the barrier close to the well gives rise to surprisingly narrow absorption peaks in the photoluminescence excitation spectra. The peaks become increasingly stronger for decreasing spacer-layer thicknesses between the quantum well and the Mn layer. Most of the peaks were identified based on self-consistent calculations; however, we observed additional peaks that cannot be identified with quantum well transitions, which origin we attribute to an enhanced exciton-phonon coupling. Finally, we discuss possible effects related to the exciton magneto-polaron complex in the reinforcement of the photoluminescence excitation peaks.11620Žutić, I., Fabian, J., Sarma, S.D., (2004) Rev. Mod. Phys., 76, p. 323Dielt, T., Ohno, H., (2014) Rev. Mod. Phys., 86, p. 187Tanaka, M., Ohya, S., Hai, P.N., (2014) Appl. Phys. Rev., 1, p. 011102Krebs, O., Benjamin, E., Lemaître, A., (2009) Phys. Rev. B, 80, p. 165315Gazoto, A.L., Brasil, M.J.S.P., Iikawa, F., Brum, J.A., Ribeiro, E., Danilov, Y.A., Vikhrova, O.V., Zvonkov, B.N., (2011) Appl. Phys. Lett., 98, p. 251901Ohno, H., (1998) Science, 281, p. 951Nazmul, A.M., Amemiya, T., Shuto, Y., Sugahara, S., Tanaka, M., (2005) Phys. Rev. Lett., 95, p. 017201Korenev, V.L., Akimov, I.A., Zaitsev, S.V., Sapega, V.F., Langer, L., Yakovlev, D.R., Danilov, Y.A., Bayer, M., (2012) Nat. Commun., 3, p. 959Bobrov, A.I., Vikhrova, O.V., Danilov, Y.A., Dorokhin, M.V., Drozdov, Y.N., Drozdov, M.N., Zvonkov, B.N., Pavlova, E.D., (2014) Bull. Russ. Acad. Sci. Phys., 78 (1), pp. 6-8Wurstbauer, U., Soda, M., Jakiela, R., Schuh, D., Weiss, D., Zweck, J., Wegscheider, W., (2009) J. Cryst. Growth, 311 (7), p. 2160Poggio, M., Myers, R.C., Stern, N.P., Gossard, A.C., Awschalom, D.D., (2005) Phys. Rev. B, 72, p. 235313Balanta, M.A.G., Brasil, M.J.S.P., Iikawa, F., Mendes, U.C., Brum, J.A., Maialle, M.Z., Danilov, Y.A., Zvonkov, B.N., (2013) J. Phys. D: Appl. Phys., 46, p. 215103Lee, K.-S., Lee, C.-D., Kim, Y., Noh, S.K., (2003) Solid State Commun., 128, p. 177Hou, H.Q., Staguhn, W., Takeyama, S., Miura, N., Segawa, Y., Aoyagi, Y., Namba, S., (1991) Phys. Rev. B, 43, p. 4152Wu, J.-W., Nurmikko, A.V., Quinn, J.J., (1986) Phys. Rev. B, 34, p. 1080(1986) Solid State Commun., 57, p. 853Gonc¸alves Da Silva, C.E.T., (1985) Phys. Rev. B, 32, p. 6962Zhang, X.-C., Chang, S.-K., Nurmikko, A.V., Kolodziejski, L.A., Gunshor, R.L., Datta, S., (1985) Phys. Rev. B, 31, p. 4056Zhang, X.-C., Chang, S.-K., Nurmikko, A.V., Kolodziejski, L.A., Gunshor, R.L., Datta, S., (1985) Solid State Commun., 56, p. 255Zhang, X.-C., Chang, S.-K., Nurmikko, A.V., Kolodziejski, L.A., Gunshor, R.L., Datta, S., (1985) Appl. Phys. Lett., 47, p. 59Yakovlev, D.R., Ossau, W., (2010) Introduction to the Physics of Diluted Magnetic Semiconductors, p. 221. , edited by J. Kosut and J. A. Gaj Springer, Chap. 7Preisler, V., Grange, T., Ferreira, R., De Vaulchier, L.A., Guldner, Y., Teran, F.J., Potemski, M., Lemaitre, A., (2006) Phys. Rev. B, 73, p. 075320Verzelen, O., Bastard, G., Ferreira, R., (2000) Phys. Rev. B, 62, p. R4809Verzelen, O., Bastard, G., Ferreira, R., (2002) Phys. Rev. B, 66, p. 081308RDickmann, S., Tartakovskii, A.I., Timofeev, V.B., Zhilin, V.M., Zeman, J., Martinez, G., Hvam, J.M., (2000) Phys. Rev. B, 62, p. 2743Lucovsky, G., Chen, M.F., (1970) Solid State Commun., 8, pp. 1397-140

Optical and spin properties of localized and free excitons in GaBi ₓAs₁-ₓ /GaAs multiple quantum wells

Raman spectroscopy and magneto-photoluminescence measurements under high magnetic fields were used to investigate the optical and spin properties of GaBiAs/GaAs multiple quantum wells (MQWs). An anomalous negative diamagnetic energy shift was observed at higher temperatures and higher laser intensities, which was associated to a sign inversion of hole effective mass in these structures. In addition, an enhancement of the polarization degree with decreasing of laser intensity was observed (experimental condition where the emission is dominated by localized excitons). This effect was explained by changes of spin relaxation and exciton recombination times due to exciton localization by disorder

Revealing the nature of low temperature photoluminescence peaks by laser treatment in van der Waals epitaxially grown WS2 monolayers

Monolayers of transition metal dichalcogenides (TMD) are promising materials for optoelectronics devices. However, one of the challenges is to fabricate large-scale growth of high quality TMD monolayers with the desired properties in order to expand their use in potential applications. Here, we demonstrate large-scale tungsten disulfide (WS2) monolayers grown by van der Waals Epitaxy (VdWE). We show that, in addition to the large structural uniformity and homogeneity of these samples, their optical properties are very sensitive to laser irradiation. We observe a time instability in the photoluminescence (PL) emission at low temperatures in the scale of seconds to minutes. Interestingly, this change of the PL spectra with time, which is due to laser induced carrier doping, is employed to successfully distinguish the emission of two negatively charged bright excitons. Furthermore, we also detect blinking sharp bound exciton emissions which are usually attractive for single photon sources. Our findings contribute to a deeper understanding of this complex carrier dynamics induced by laser irradiation which is very important for future optoelectronic devices based on large scale TMD monolayers

Revealing the nature of low temperature photoluminescence peaks by laser treatment in van der Waals epitaxially grown WS2 monolayers

Monolayers of transition metal dichalcogenides (TMD) are promising materials for optoelectronics devices. However, one of the challenges is to fabricate large-scale growth of high quality TMD monolayers with the desired properties in order to expand their use in potential applications. Here, we demonstrate large-scale tungsten disulfide (WS2) monolayers grown by van der Waals Epitaxy (VdWE). We show that, in addition to the large structural uniformity and homogeneity of these samples, their optical properties are very sensitive to laser irradiation. We observe a time instability in the photoluminescence (PL) emission at low temperatures in the scale of seconds to minutes. Interestingly, this change of the PL spectra with time, which is due to laser induced carrier doping, is employed to successfully distinguish the emission of two negatively charged bright excitons. Furthermore, we also detect blinking sharp bound exciton emissions which are usually attractive for single photon sources. Our findings contribute to a deeper understanding of this complex carrier dynamics induced by laser irradiation which is very important for future optoelectronic devices based on large scale TMD monolayers