T. Gregorkiewicz

Direct bandgap optical transitions in Si nanocrystals (2009)

Prokofiev, A. A., Moskalenko, A. S., Yassievich, I. N., Timmerman, D., Zhang, H., ...

It is demonstrated that for spherical silicon dots, quantum confinement leads to the decrease of the direct energy gap at the $\Gamma$-point. We postulate to identify the efficient blue emission from...

Energy transfer processes in Er-doped SiO2 sensitized with Si nanocrystals (2008)

Izeddin, I., Timmerman, D., Gregorkiewicz, T., Moskalenko, A. S., Prokofiev, A. A., Yassievich, I. N., ...

We present a high-resolution photoluminescence study of Er-doped SiO2 sensitized with Si nanocrystals (Si NCs). Emission bands originating from recombination of excitons confined in Si NCs and of...

Space-separated quantum cutting with silicon nanocrystals for photovoltaic applications (2008)

Timmerman, D., Izeddin Aguirre, I., Stallinga, P. Dr., Yassievich, I.N., Gregorkiewicz, T.

For optimal energy conversion in photovoltaic devices (electricity to and from light) one important requirement is that the full energy of the photons is used. However, in solar cells, a single...

Mid-infrared spectroscopy of the Er-related donor state in Si/Si:Er3+ nanolayers (2008)

Izeddin, I., Klik, M.A.J., Vinh, N.Q., Bresler, M.S., Gregorkiewicz, T.

We present experimental evidence on the donor level related to optical properties of the Er3+ ion in crystalline silicon. Using two-color spectroscopy with a free-electron laser we provide a direct...

Electron paramagnetic resonance study of centres involved in storage processes in K2YF5: RE thermoluminescent phosphors (2008)

Vrielinck, H., Zverev, D., Smet, P.F., Poelman, D., Gregorkiewicz, T., Callens, F.

Ce3+- and Th3+-activated K2YF5 crystals, which have been shown to exhibit thermoluminescence (TL) response to alpha, beta, gamma and X-rays, are investigated using electron paramagnetic resonance...

Energy transfer in Er-doped SiO2 sensitized with Si nanocrystals (2008)

Izeddin, I., Timmerman, D., Gregorkiewicz, T., Moskalenko, A.S., Prokofiev, A.A., Yassievich, I.N., ...

We present a high-resolution photoluminescence study of Er-doped SiO2 sensitized with Si nanocrystals (Si NCs). Emission bands originating from recombination of excitons confined in Si NCs, internal...

Pump-probe investigations of THz transitions in Si/Si:Er3+ nanolayers (2008)

Minissale, S., Vinh, N.Q., Gregorkiewicz, T.

A possibility to realize optical transitions within the I-4(15/2) ground state of Er3+ ion in Si, between levels split by crystal-field, has been investigated by pump-probe technique. The study has...

Microscopic evidence for role of oxygen in luminescence of Er3+ ions in Si: Two-color and pump-probe spectroscopy (2008)

Minissale, S., Vinh, N.Q., Boer, W. De, Bresler, M.S., Gregorkiewicz, T.

Influence of oxygen on optical activity and thermal stability of the 1.5 µm emission of Er3+ ions in Si is well documented. Here we support this predominantly phenomenological notion with...

Er3+ photoluminescence excitation spectra in erbium-doped epitaxial silicon structures (2004)

Andreev, B.A., Krasil'nik, Z.F., Kryzhkov, D.I., Yablonskii, A.N., Kuznetsov, V.P., Gregorkiewicz, T., ...

Excitation spectra of erbium photoluminescence (λ = 1540 nm) in Si : Er epitaxial structures were studied within a broad pump wavelength range (λ = 780–1500 nm). Erbium photoluminescence was...