Symmetry and optical anisotropy in CdSe-ZnSe quantum dots [Elektronische Ressource] / vorgelegt von Tobias Kießling

Sujets

• Physik

Informations

• Publié par: julius-maximilians-universitat_wurzburg
• Publié le: 01 janvier 2009
• Nombre de lectures: 31
• Poids de l'ouvrage: 3 Mo

Extrait

Symmetry and Optical Anisotropy
in CdSe/ZnSe Quantum Dots
Dissertation zur Erlangung des
naturwissenschaftlichen Doktorgrades
der Bayerischen Julius-Maximilians-Universita¨tWu¨rzburg
vorgelegt von
Tobias Kießling
aus Wu¨rzburg
Wu¨rzburg 2009Eingereicht am 27.07.2009
bei der Fakult¨at fu¨r Physik und Astronomie
Gutachter der Dissertation:
1. Gutachter: Prof. Dr. W. Ossau
2. Gutachter: Prof. Dr. L. W. Molenkamp
Pru¨fer im Promotionskolloquium:
1. Pru¨fer: Prof. Dr. W. Ossau
2. Pru¨fer: Prof. Dr. L. W. Molenkamp
3. Pru¨fer: Prof. Dr. B. Trauzettel
Tag des Promotionskolloquiums: 29.10.2009
Doktorurkunde ausgeh¨andigt am: ...Publications i
Parts of this thesis have been already published :
• S. Mahapatra, C. Schumacher, T. Kiessling, G. V. Astakhov, U. Bass, W. Ossau,
J. Geurts and K. Brunner. CdSe/ZnSe Quantum Dots formed by low temperature
epitaxy an In-situ annealing: Properties and growth optimization. Acta Phys. Pol.
A 108, 769 (2005)
• G.V.Astakhov,T. Kiessling,A.V.Platonov,T.Slobodskyy,S.Mahapatra,W.Os-
sau, G. Schmidt, K. Brunner and L. W. Molenkamp. Circular-to-linear and linear-
to-circular conversion of optical polarization by semiconductor quantum dots. Phys.
Rev. Lett. 96, 027402 (2006)
Selected forVirtualJournalofNanoscaleScience & Technology, 30thJanuary2006,
nanomagnetism and spintronics (http://www.vjnano.org/).
• T. Kiessling, G. V. Astakhov, A. V. Platonov, T. Slobodskyy, S. Mahapatra,
W. Ossau, G. Schmidt, K. Brunner and L. W. Molenkamp. Optical anisotropy
of CdSe/ZnSe quantum dots. Phys. Stat. Sol. (c) 3, pp. 912-915 (2006)
• A. V. Platonov, T. Kiessling, G. V. Astakhov, A. A. Maksimov, A. V. Larionov,
D. R. Yakovlev, T. Slobodskyy, W. Ossau, G. Schmidt, K. Brunner, M. Bayer and
L. W. Molenkamp. Energy relaxation in CdSe/ZnSe quantum dots under the strong
exciton-phonon coupling regime. Phys. Stat. Sol. (c) 3, pp. 924-927 (2006)
• S. Mahapatra, K. Brunner, C. Schumacher, T. Kiessling, G. V. Astakhov, U. Bass,
E.Margapoti,W.Ossau,JGeurts,L.Worschech,A.ForchelandL.W.Molenkamp.
Comparative study of self-assembled CdSe/ZnSe quantum dots grown by variants of
conventional MBE. Phys. Stat. Sol. (c) 3, pp. 928-932 (2006)
• T. Kiessling,A.V.Platonov,G.V.Astakhov,T.Slobodskyy,S.Mahapatra,W.Os-
sau, G. Schmidt, K.Brunner andL. W. Molenkamp. Anomalous in-plane magneto-
optical anisotropy of self-assembled quantum dots. Phys. Rev. B 74, 041301R
(2006)
Selected for Virtual Journal of Nanoscale Science & Technology, 24th July 2006,
quantumcoherence,computing,andinformationstorage(http://www.vjnano.org/).
• T. Kiessling,A.V.Platonov,G.V.Astakhov,S.Mahapatra,T.Slobodskky,W.Os-
sau, G. Schmidt, K. Brunner and L. W. Molenkamp. Phonon replica fine structure
in Cd/Se quantum dots. Proc. 14th Int. Symp. ’Nanostructures: Physics and
Technology’ pp. 269, St. Petersburg, Russia, June 26-30, 2006.ii Publications
• A.V.Platonov,T. Kiessling,G.V.Astakhov,T.Slobodskyy,S.Mahapatra,W.Os-
sau, G. Schmidt, K. Brunner, L. W. Molenkamp. Anomalous in-plane magneto-
optical anisotropy of self-assembled quantum dots. Proc. 14th Int. Symp. ’Nanos-
tructures: Physics and Technology’ pp.146-147, St.Petersburg, Russia, June 26-30,
2006.
• S. Mahapatra, T. Kiessling, E. Margapoti, G. V. Astakhov, W. Ossau,
L. Worschech, A. Forchel and K. Brunner. Formation mechanism and properties
of CdSe quantum dots on ZnSe by low temperature epitaxy and in-situ annealing.
Appl. Phys. Lett. 89, 043102 (2006)
• S. Mahapatra, T. Kiessling, E. Margapoti, G. V. Astakhov, W. Ossau,
L. Worschech, A. Forchel and K. Brunner. Layer-by-layer growth and island forma-
tion in CdSe/ZnSe heteroepitaxy. J. Crystal Growth 301, 00310 (2007)
• T. Kiessling,G.V.Astakhov,A.V.Platonov,S.Mahapatra,T.Slobodskyy,W.Os-
sau, G. Schmidt, K. Brunner and L. W. Molenkamp. Optical studies of structural
and magnetic anisotropies in epitaxial CdSe/ZnSe quantum dots. Phys. Stat. Sol.
(c) 4, 3324 (2007).
• S, Mahapatra, T. Kiessling, E. Margapoti, G. V. Astakhov, J. Renner, U. Bass,
C.Bougerol,T.Schmidt, A.Bendounan, F.Schmitt, C.Schumacher, L.Worschech,
W. Ossau, J. Geurts, L. W. Molenkamp, F. Reinert, A. Forchel and K. Brunner.
CdSe/ZnSeheteroepitaxy: Aspects ofgrowthandselforganizationofnanostructures.
Phys. Stat. Sol. (c) 4, 3129 (2007).
Further parts of this Thesis are currently prepared for publication.Publications iii
Further publications under participation of the author :
• G. V. Astakhov, T. Kiessling, D. R. Yakovlev, E. A. Zhukov, M. Bayer, W. Ossau,
B. P. Zakharchenya, G. Karczewski, T. Wojtowicz and J. Kossut. Nanosecond spin
memory of electrons in CdTe/CdMgTe quantum wells. Phys. Stat. Sol. (b) 243,
pp. 858-862 (2006).
• H. Hoffmann, G. V. Astakhov, T. Kiessling, W. Ossau, G. Karczewski, T. Wojtow-
icz, J. Kossut and L. W. Molenkamp. Optical spin pumping of modulation doped
electrons probed by a two-color Kerr rotation technique. Phys. Rev. B 74, 071407
(2006)
Selected for Virtual Journal of Nanoscale Science & Technology, 4th September
2006, nanomagnetism and spintronics (http://www.vjnano.org/).
• G. V. Astakhov, R. I. Dzhioev, K. V. Kavokin, V. L. Korenev, M. V. Lazarev,
M. N. Tkachuk, Yu. G. Kusrayev, T. Kiessling, W. Ossau, and L. W. Molenkamp.
Suppression of electron spin relaxation in Mn-doped GaAs. Phys. Rev. Lett. 101,
076602 (2008).
• G. V. Astakhov, H. Hoffmann, V. L. Korenev, T. Kiessling, J. Schwittek,
G. M. Schott, C. Gould, W. Ossau, K. Brunner, and L. W. Molenkamp. Nonther-
mal Photocoercivity effect in a low doped (Ga,Mn)As ferromagnetic semiconductor.
Phys. Rev. Lett. 102, 187401 (2009).iv ContentsContents
Zusammenfassung 1
Summary 5
1 Introduction 9
2 Fundamental properties of semiconductor quantum dots 17
2.1 Discrete energy spectrum of quantum dots . . . . . . . . . . . . . . . . . . 17
2.2 Properties of quantum confined solid state systems . . . . . . . . . . . . . 20
2.3 Modeling of real quantum dots. . . . . . . . . . . . . . . . . . . . . . . . . 24
3 Optical Properties of epitaxial semiconductor quantum dots 29
3.1 Optical properties of direct gap zinc-blende type compound semiconductors 30
3.1.1 Crystal symmetry and band structure . . . . . . . . . . . . . . . . . 31
3.1.2 Radiative band-to-band recombination at k = 0 . . . . . . . . . . . 34
3.1.3 Excitons and the concept of Poincar´e and Bloch spheres . . . . . . 36
3.2 Excitons confined to epitaxial QD nanostructures . . . . . . . . . . . . . . 39
3.2.1 Neutral excitons in magnetic fields . . . . . . . . . . . . . . . . . . 43
3.2.2 Exciton complexes in the absence of magnetic field . . . . . . . . . 44
4 Quantum dot fabrication 49
4.1 General remarks on molecular beam heteroepitaxy . . . . . . . . . . . . . . 50
4.2 Self-assembled quantum dot growth . . . . . . . . . . . . . . . . . . . . . . 51
4.3 Growth variants of CdSe/ZnSe quantum dots . . . . . . . . . . . . . . . . 55
4.3.1 Conventional MBE growth . . . . . . . . . . . . . . . . . . . . . . . 55
4.3.2 Low temperature epitaxy and in-situ annealing . . . . . . . . . . . 57
4.4 Conventional MBE versus low temperature epitaxy QD luminescence . . . 60
5 Electronic Properties of shallow CdSe/ZnSe Quantum Dots 63
5.1 Electronic structure and composition . . . . . . . . . . . . . . . . . . . . . 64
5.2 Exciton-phonon interaction. . . . . . . . . . . . . . . . . . . . . . . . . . . 71
5.2.1 Experimental results . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.2.2 Analysis and discussion . . . . . . . . . . . . . . . . . . . . . . . . . 75
vvi Contents
6 Optical anisotropy of CdSe/ZnSe quantum dots 79
6.1 Optical anisotropy in the absence of magnetic fields . . . . . . . . . . . . . 80
6.1.1 Optical polarization anisotropy and polarization conversion . . . . . 80
6.1.2 Optical polarization alignment and ensemble symmetry . . . . . . . 86
6.2 Optical anisotropy induced by in-plane magnetic fields . . . . . . . . . . . 89
6.2.1 Experimental results . . . . . . . . . . . . . . . . . . . . . . . . . . 89
6.2.2 Qualitative discussion . . . . . . . . . . . . . . . . . . . . . . . . . 94
6.2.3 Quantitative analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6.2.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7 Conclusions and Outlook 109
Appendix 113
A Setup and experimental methods 113
A.1 Experimental setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
A.2 Optical polarization modulation spectroscopy . . . . . . . . . . . . . . . . 115
B Angular Momentum Operators 117
C List of Abbreviations 119
Bibliography 121Zusammenfassung
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