Spatially direct and indirect transitions observed for Si/Ge quantum dots

Larsson, M.; Elfving, A.; Holtz, P. O.; Hansson, G. V.; Ni, W.-X.
June 2003
Applied Physics Letters;6/30/2003, Vol. 82 Issue 26, p4785
Academic Journal
The optical properties of Ge quantum dots embedded in Si were investigated by means of photoluminescence, with temperature and excitation power density as variable parameters. Two different types of recombination processes related to the Ge quantum dots were observed. A transfer from the spatially indirect to the spatially direct recombination in the type-II band lineup was observed with increasing temperature. A blueshift of the spatially indirect Ge quantum-dot-emission energy with increasing excitation power is ascribed to band bending at the type-II Si/Ge interface for high carrier densities. Comparative studies were performed on uncapped Ge dot structures.


Related Articles

  • Evolution and stability of ordered SiGe islands grown on patterned Si(100) substrates. Dais, C.; Mussler, G.; Sigg, H.; Müller, E.; Solak, H. H.; Grützmacher, D. // Journal of Applied Physics;Jun2009, Vol. 105 Issue 12, p122405-1 

    SiGe quantum dots are proposed as building blocks for future Si device technology. However, in order to exploit the full potential of SiGe islands, it is necessary to control their positioning and size on a nanometer length. This is achieved by templated self-assembly, which combines substrate...

  • Staircase-like spectral dependence of ground-state luminescence time constants in high-density InAs/GaAs quantum dots. Mazur, Yu. I.; Tomm, J. W.; Petrov, V.; Tarasov, G. G.; Kissel, H.; Walther, C.; Zhuchenko, Z. Ya.; Masselink, W. T. // Applied Physics Letters;5/21/2001, Vol. 78 Issue 21, p3214 

    Time-resolved photoluminescence (PL) from InAs/GaAs quantum dots with a bimodal size distribution is used to investigate the dynamic carrier-transfer processes which couple transfer between similarly sized quantum dots and between quantum dots in different size categories. The relationship...

  • Influence of GaAs capping on the optical properties of InGaAs/GaAs surface quantum dots with 1.5 μm emission. Saito, Hideaki; Nishi, Kenichi; Sugou, Shigeo // Applied Physics Letters;11/9/1998, Vol. 73 Issue 19 

    Uncapped InGaAs quantum dots (surface quantum dots) on a GaAs substrate emit photoluminescence at a long wavelength of 1.53 μm at room temperature. When the surface dots are covered by a GaAs cap layer, the emission energy of the dots increases by 287 meV. This large energy shift is mainly...

  • Influence of growth conditions on the photoluminescence of self-assembled InAs/GaAs quantum dots. Chu, L.; Arzberger, M. // Journal of Applied Physics;2/15/1999, Vol. 85 Issue 4, p2355 

    Presents information on a study which investigated the influence of various growth parameters on the optical properties of self-assembled quantum dots. Experimental details; Results and discussion; Conclusion.

  • Photoluminescence of CdSe nanocrystallites embedded in BaTiO[sub 3] matrix. Zhou, Ji; Li, Longtu; Gui, Zhilun; Buddhudu, S.; Zhou, Yan // Applied Physics Letters;3/20/2000, Vol. 76 Issue 12, p1540 

    This letter reports the photoluminescence properties of CdSe quantum dots (QDs) embedded in a ferroelectric BaTiO[sub 3] matrix. The main emission from the samples has been assigned to the band-edge transition of QDs. With an increase in the heat treatment temperature, the emission peak has been...

  • Structural and optical properties of vertically aligned InP quantum dots. Zundel, M.K.; Specht, P. // Applied Physics Letters;11/17/1997, Vol. 71 Issue 20, p2972 

    Examines the influence of stacking of indium phosphide quantum dot layers on the photoluminescence energy, intensity and linewidth. Preparation of the layers by molecular beam epitaxy; Use of transmission electron microscopy; Effect of the reduction of dot layer distance on material homogeneity.

  • Synthesis, structure, and optical properties of colloidal GaN quantum dots. Micic, O.I.; Ahrenkiel, S.P. // Applied Physics Letters;7/26/1999, Vol. 75 Issue 4, p478 

    Examines the synthesis, structure and optical properties of colloidal gallium nitride quantum dots. Reaction of dimeric amidogallium with ammonia at room temperature; Photoluminescence excitation spectrum showing two excited-state transitions.

  • Magnetophotoluminescence of stacked self-assembled InP quantum dots. Provost, R.; Hayne, M. // Applied Physics Letters;8/9/1999, Vol. 75 Issue 6, p799 

    Examines the magnetophotoluminescence measurements of stacked layers of self-assembled semiconductor quantum dots. Determination of the exciton reduced mass from the field dependence of the photoluminescence energy; Application of a magnetic field perpendicular to the growth direction; Decrease...

  • High-temperature light emission from InAs quantum dots. Patane, A.; Polimeni, A. // Applied Physics Letters;8/9/1999, Vol. 75 Issue 6, p814 

    Studies the photoluminescence (PL) properties from self-assembled quantum dots. Use of power excitation densities to identify the contribution of nonradiative channels; Role played by the wetting layer on the dot PL intensity.


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics