Showing papers in "Journal of Luminescence in 1993"

TL;DR: In this paper, the origin of visible luminescence from porous Si is argued in terms of a quantum well picture including a spectrum of Si-related states localized on the surface.

TL;DR: In this paper, a detailed spectroscopic study of highly porous silicon was carried out, and the observation of momentum-conserving phonon satellites in resonantly excited photoluminescence (PL) spectra enabled the luminescent material in porous silicon to be unambiguously identified as crystalline silicon.

TL;DR: In this paper, the influence of low-energy matrix excitations on the line widths and fluorescence correlation of single terrylene molecules in polyethylene at helium temperatures was studied.

TL;DR: In this article, optical absorption, luminescence, saturation of absorption and lifetime measurements have been carried out on Co-doped MgAl 2 O 4, and the crystal field parameter Dq of 400 cm -1 and the Racah parameters B of 730 cm - 1 and C of 3500 cm -2 are estimated for the tetrahedral Co 2+ ion.

TL;DR: The electroluminescence of porous silicon and its application are reported in this paper, the basic structures are described, the main tasks for the work in the next future are discussed.

TL;DR: In this article, the vibronic transition probabilities for the strong and narrow vibronics were determined accurately in both excitation and emission for LiBaF3:Eu2+ ion in a site with inversion symmetry.

TL;DR: In this article, an interpretation of the experimental low-temperature behavior of the radiative lifetime of Jaggregated dye solutions is proposed, and an estimate of the intermolecular dipole-dipole interaction is made that differs from the experimental value obtained by measuring the shift of the dimer absorption band maximum relative to that of monomer.

TL;DR: In this paper, a variety of spectral diffusion effects, including spontaneous resonance frequency changes on the 10-100 MHz scale which lead to apparent fluctuations in the absorption line width and shape, discontinuous jumps in the resonance frequency of 100-2000 MHz on a time scale longer than 2.5 s, and long-lived light-induced changes in resonance frequency, were observed for some molecules.

TL;DR: In this paper, the optical and luminescence properties of annealed siloxene and porous silicon are compared in detail, and new experimental results based on optically detected magnetic resonance provide microscopic information about radiative states in porous Si which is incompatible with the conventional quantum confinement model.

TL;DR: In this article, the orientations of the transition dipole moments of single pentacene molecules located in the O-1 and O-2 sites of p-terphenyl were investigated.

TL;DR: In this article, the physical origin of the luminescence bands of porous silicon is discussed using results of calculations of electronic and optical properties of silicon nanostructures, and it is shown that polysilanes can emit visible light in some cases but with radiative lifetimes in the nanosecond range.

TL;DR: In this paper, a new comprehensive approach to the radiative processes in octahedrally coordinated Cr 3+ is presented, which is described by the electronic manifolds defined by total electronic energies dependent on the positions of the ions, calculated with inclusion of spin-orbit and electron-phonon interactions, and related to them discrete oscillation states.

TL;DR: In this article, it is shown that the passivation of the internal surface of pores determines not only the intensity but also the spectral dependence of the luminescence of the pores.

TL;DR: In this paper, the authors analyze the evolution of the splitting of the 6P7/2 energy level in the mixed crystals and show that the lowering of the site symmetry from Oh to C2v induces a fourth component to grow up.

TL;DR: The tetravalent vanadium ion (V4+) is isoelectronic to Ti3+ and therefore has promising aspects for tunable solid state lasers as mentioned in this paper, where crystal growth and spectroscopic characterization of V4+ -doped Al2O3 and YAlO3 are presented.

TL;DR: In this article, spectroscopic investigations of the near infrared (NIR) laser center in chromium doped Y 2 SiO 5 (YSO) were performed, and the results were most consistent with the NIR center being attributed to Cr 4+ in a distorted tetrahedral site.

TL;DR: In this article, photoluminescence at 154 μm has been observed from discontinuous βFeSi 2 layers fabricated by ion beam synthesis in silicon wafers, measured at 5 K, from a sample implanted to a dose of 2 × 10 17 Fe ions cm −2 at an energy of 200 ke V, after an 18h anneal at 920°C.

TL;DR: In this paper, a spectral hole burning of Sm 2+ in a glass system at room temperature was observed, and the hole was burned at 680.3 nm with 230 mW laser light and was observed via the excitation spectrum.

TL;DR: In this article, the authors review the luminescence properties of porous silicon layers formed on p-type silicon substrates and subsequently oxidized by anodic polarization in an aqueous electrolyte.

TL;DR: In this article, it was shown that the capture of an electron or a hole by a neutral dangling bond is a nonradiative process in crystallites with bandgaps smaller than 2.2 eV.

TL;DR: In this article, the widths, positions and shapes of sharp luminescence lines of the Nd3+ ion in GSGG:Cr3+, Nd 3+ were measured carefully from 78 to 600 K. The Debye temperature of GSGG is estimated to be 500 K through the fitting of the theoretical formulas to the experimental data.

TL;DR: In this paper, the optical properties of Tm3+-doped LiNbO3 and MgO3 (MgO) have been measured and it has been found that the 1D2, 1G4, 3H4 and 3F4 levels decay radiatively having temperature independent lifetimes.

TL;DR: In this paper, X-band electron paramagnetic resonance spectroscopy was applied to the study of the dopants in n+-type and the defects in n-and p-type porous silicon of both high and low porosity.

TL;DR: In this paper, the excited state absorption (ESA) in a CaWO 4 under excimer laser excitation (308 nm) was reported and the ESA spectrum proved to be very broad and intense.

TL;DR: In this paper, the lifetimes of the 5 D 0 state and the phonon side bands in these glasses were measured and it was found that the addition of chloride ions had a great effect to increase the radiative transition rate.

TL;DR: In this article, the optical properties of Sm 2+ -doped fluoride glasses having three different compositions were investigated and the absorption and emission spectra revealed that the immediate fluorine environment surrounding the Sm 2 + ion is nearly identical for the three glass compositions, and is probably characterized by a high coordination number.

TL;DR: In this paper, the electrochemical deposition of electrically active polyaniline films (PANI) onto the surface of porous silicon (PS) layers formed at p- and n-type silicon wafers has been studied using cyclic voltammetry measurements and infrared spectroscopy.

TL;DR: In this article, it is known from Fourier transform infrared (FT-IR) measurements that the SiO 2 covering on pore walls has discontinuities where the surface states are terminated by hydrogen.

TL;DR: In this article, the frequency dependence of the conductivity of various samples of porous silicon in the regime 10 Hz to 100 kHz at different temperatures was measured. But the conductivities in this regime are only weakly temperature dependent, which suggests that the density of state at the Fermi level is finite.

TL;DR: In this article, the authors report on the preparation of thin films of light emitting nanocrystalline silicon by plasma CVD and post-oxidation and verify theoretical predictions of the increase of the luminescence efficiency with decreasing crystalline size.