Spatially resolved spectroscopy on single self-assembled quantum dots

Zrenner, A.; Markmann, M.; Beham, E.; Findeis, F.; Böhm, G.; Abstreiter, G.

doi:10.1007/s11664-999-0109-8

Cited by 24 publications

(9 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1b) showing I1 and I2 at 1.152 and 1.239 eV, respectively. Qualitatively similar results have been reported for single InGaAs QDs in the few-body regime [20]. Both the line positions and the spacing of the excited state transitions depend on the QD population, demonstrating the importance of many-body effects in self-organized QDs providing strong carrier confinement.…”

supporting

confidence: 84%

See 1 more Smart Citation

Excited States of InAs/GaAs Quantum Dots

Heitz

Guffarth

Mukhametzhanov

et al. 2001

phys. stat. sol. (b)

View full text Add to dashboard Cite

Exciton properties of self-organized InAs/GaAs QDs are investigated. Size-selective spectroscopy reveals the excited single-exciton transition spectrum and enhanced polar exciton-LO-phonon coupling. A good qualitative understanding of the experimental results is achieved by eight-band k Á p calculations. Renormalization of the single-exciton spectrum in highly populated QDs shows the importance of many-particle interactions in the strong confinement limit. The ground state transition energy decreases by $16 meV for QDs occupied with $18 excitons.The formation of coherently embedded nm-sized islands in Stranski-Krastanov growth has evolved as a powerful means to produce high-quality nm-scale quantum dots (QDs) with large substrate splitting [1]. The large spread of possible structural properties, the limited characterization methods, and the sophisticated numerical approaches required to predict the electronic spectrum in such strained low-dimensional structures have hampered a detailed identification of optical transitions, yet. In particular the excited state transition spectrum depends on the structural properties of the QDs [2, 3].Here we report on the electronic properties of self-organized QDs in the InAs/GaAs model material system, comparing results of high-density photoluminescence (PL) and PL excitation (PLE) spectroscopy. The results are discussed on the basis of eight-band k Á p calculations for idealized pyramidal InAs/GaAs QDs [2]. The investigated samples (dubbed S300, P300, and V300) were grown by molecular beam epitaxy on semi-insulating GaAs(001) as described in detail in Refs. [4,5]. Structural characterization yields island densities > 400 mm --2 and suggests pyramidal shapes with base lengths between $14 and $19 nm. The optical properties of the samples have been studied in detail recently [6][7][8].Two complementary methods are currently used to access the excited state transition spectrum of QDs. On one hand, state filling in PL (see, e.g. Fig. 1a) is commonly used to observe excited state transitions [9][10][11]. The inhomogeneous broadening and manyparticle effects limit, however, the value of comparisons with single-particle or singleexciton models. On the other hand, PLE experiments (see, e.g. Fig. 1b) probe size-selectively the QD absorption spectrum [12], provided intradot relaxation is faster than competing recombination processes [8]. Figure 2a shows PLE spectra of the V300 sam-1 ) Corresponding author;

show abstract

supporting

confidence: 84%

“…Different electron and hole wave functions lead to a breakdown of hidden symmetries [17] since the repulsive e-e and h-h and the attractive e-h Coulomb terms are no longer balanced. Both positive [20] and negative [22] bi-exciton binding energies have been reported for single InGaAs QDs, hinting to a decisive influence of the particular confinement.…”

mentioning

confidence: 99%

Excited States of InAs/GaAs Quantum Dots

Heitz

Guffarth

Mukhametzhanov

et al. 2001

phys. stat. sol. (b)

View full text Add to dashboard Cite

show abstract

“…In these experiments, the photoluminescence spectra in magnetic field are studied. [37][38][39] The g factor of hole was derived from experimental value of exciton g factor g ex and electron g factor g e , using the equation g ex ϭg h Ϯg e ͑''Ϫ'' for bright excitons, ''ϩ'' for dark exci-tons͒. To avoid the systematic inaccuracy caused by existing of exchange interaction between electron and hole, one must carry out the experiment with ''free'' hole ͑not bounded in exciton͒.…”

Section: Discussionmentioning

confidence: 99%

Wave functions andgfactor of holes in Ge/Si quantum dots

2003

View full text Add to dashboard Cite

We investigate theoretically the Zeeman effect on the hole states in quantum dots. In frame of tight-binding approach, we propose a method of calculating the g factor for localized states. The principal values of the g factor for the ground hole state in the self-assembled Ge/Si quantum dot are calculated. We find the strong g-factor anisotropy-the components g xx , g yy are one order smaller than the g zz component, g zz ϭ12.28, g xx ϭ0.69, g yy ϭ1.59. The efficiency of the developed method is demonstrated by calculating of the size dependence of g factor and by establishment of the connection with two-dimensional case. The g-factor anisotropy increases with the size of the quantum dot. The analysis of the wave function structure shows that the g factor and its size dependence are mainly controlled by the contribution of the state with J z ϭϮ 3 2 , where J z is the angular momentum projection on the growth direction of the quantum dot.where , are the azimuth and polar angles of the vector h in the coordinate system (x,y,z) and the matrix R can be expressed via standard rotation matrix: R

show abstract

“…The variation of the exciton density of states of a single self-assembled quantum dot [1,3] with size has been measured by photoluminescence excitation spectroscopy (PLE) [39,40,41,42,43]. New features in the absorption spectra, previously hidden in spectra from large ensembles of dots due to inhomogeneous broadening [44], were observed.…”

Section: Excitons In Jacobi Coordinatesmentioning

confidence: 99%

Electronic Properties of Self-Assembled Quantum Dots

Hawrylak

Korkusiński

2003

Topics in Applied Physics

View full text Add to dashboard Cite

Abstract. Theoretical investigation of electronic and optical properties of selfassembled quantum dots is reviewed. The single particle states of lens-shaped, diskshaped, and vertically coupled dots are discussed. The spectrum of a single exciton, the exciton in the presence of many electrons, and many-exciton complexes are covered. The emission, absorption, far infrared spectroscopy, capacitance, photocurrent spectroscopy and inelastic light scattering as a probe of the ground and excited states of quantum dots charged with electrons and excitons are discussed.

show abstract

Spatially resolved spectroscopy on single self-assembled quantum dots

Cited by 24 publications

References 20 publications

Excited States of InAs/GaAs Quantum Dots

Excited States of InAs/GaAs Quantum Dots

Wave functions andgfactor of holes in Ge/Si quantum dots

Electronic Properties of Self-Assembled Quantum Dots

Contact Info

Product

Resources

About