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Effect of Hydrostatic Pressure on Photoluminescence Spectra from Structures with Si Nanocrystals Fabricated in SiO_2 Matrix

100%

Zhuravlev K., Tyschenko I., Vandyshev E., Bulytova N., Misiuk A., Rebohle L., Skorupa W.

Acta Physica Polonica A

2002

vol. 102

issue 2

337-344

The effect of hydrostatic pressure applied at high temperature on photoluminescence of Si-implanted SiO_2 films was studied. A "blue"-shift of PL spectrum from the SiO_2 films implanted with Si^+ ions to total dose of 1.2×10^{17} cm^{-2} with an increase in hydrostatic pressure was observed. For the films implanted with Si^+ ions to a total dose of 4.8×10^{16} cm^{-2} high temperature annealing under high hydrostatic pressure (12 kbar) causes a "red"-shift of photoluminescence spectrum. The "red" photoluminescence bands are attributed to Si nanocrystals while the "blue" ones are related to Si nanocrystals of reduced size or chains of silicon atoms or ≡Si-Si≡ defects. A decrease in size of Si nanocluster size occurs in result of the pressure-induced decrease in the diffusion of silicon atoms.

X-Ray Absorption Studies of Ge Layers Buried in Silicon Crystal

100%

Demchenko I., Ławniczak-Jabłońska K., Zhuravlev K., Piskorska E., Nikiforov A., Welter E.

Acta Physica Polonica A

2002

vol. 101

issue 5

709-717

Polarization-dependent X-ray absorption spectroscopy was used to study the local microstructure of Ge layers buried in silicon. The layers with thickness from 6 to 20 monolayers of Ge were grown by molecular beam epitaxy on Si substrate and were covered by Si (20 nm). To investigate the morphology of grown structures, X-ray absorption near edge structure and extended X-ray absorption fine structure analysis of the Ge K-edge was done. The performed qualitative analysis proves that X-ray absorption spectra are very sensitive to the local order in the formed structures and are sources of unique information about morphology of the buried Ge layers. Using these techniques we were able to observe the changes in atomic order around the Ge atoms in investigated buried layers and compare the formed atomic order with that in crystalline Ge. A substantial increase in intensity, broadening and chemical shift of the X-ray absorption near edge structure spectrum for 8 ML were observed. It can be related to the increase in density of electron states caused by increase in the localization of the states due to potential appearing at the Ge island boundaries and indicated the formation of quantum dots. The observed in-plane modulations of radial distribution and out-of-plane for different layers were discussed.

Microwave-Induced Delocalization of Excitons in Ternary Compounds of II-VI and III-V Semiconductors

68%

Ivanov V., Godlewski M., Khachapuridze A., Yatsunenko S., Wojtowicz T., Karczewski G., Bergman J., Monemar B., Shamirzaev T., Zhuravlev K., Leonardi K., Hommel D.

Acta Physica Polonica A

2003

vol. 103

issue 6

559-566

In this work we employ technique of optically detected cyclotron resonance for evaluation of the role of localization processes in CdTe/CdMnTe and CdMnTe/CdMgTe quantum well structures. From microwave-induced changes of excitonic emissions we evaluate magnitude of potential fluctuations (Stokes shift), correlate optically detected cyclotron resonance results with the results of time-resolved experiments and discuss nature of recombination processes in the limit of a strong localization.

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3 Acta Physica Polonica A

1 2003

2 2002

3 Zhuravlev K.

1 Bergman J.

1 Bulytova N.

1 Demchenko I.

1 Godlewski M.

1 Hommel D.

1 Ivanov V.

1 Karczewski G.

1 Khachapuridze A.

1 Leonardi K.

1 Misiuk A.

1 Monemar B.

1 Nikiforov A.

1 Piskorska E.

1 Rebohle L.

1 Shamirzaev T.

1 Skorupa W.

1 Tyschenko I.

1 Vandyshev E.

1 Welter E.

1 Wojtowicz T.

1 Yatsunenko S.

1 Ławniczak-Jabłońska K.

Search results

Effect of Hydrostatic Pressure on Photoluminescence Spectra from Structures with Si Nanocrystals Fabricated in SiO_2 Matrix

X-Ray Absorption Studies of Ge Layers Buried in Silicon Crystal

Microwave-Induced Delocalization of Excitons in Ternary Compounds of II-VI and III-V Semiconductors