Erbium Emission Research Articles

Microstructure and emission properties of Si nanograins and Er-doped silica films obtained by reactive magnetron co-sputtering

Erbium and silicon co-doped silica films have been fabricated by reactive magnetron sputtering. A correlation is made between the microstructure monitored by the hydrogen rate r H in the plasma and the photoluminescence properties. The erbium emission at 1.54 μm is enhanced by the increase of r H while no emission due to the silicon nanograins is observed. An explanation is given by the microstructure revealed by Raman spectroscopy. Increasing r H values lead to the deposition of increasingly numerous silicon nanograins whose size decreases. The assumption is made that the nanograins absorb the laser pumping light which creates electron–hole pairs. The energy resulting from their recombination is supposed to be transferred efficiently to the erbium ions.

Characterization of new erbium-doped tellurite glasses and fibers

Tellurite glasses are promising candidates for optical fiber laser and amplifier applications because of their excellent optical and chemical properties. The emission spectrum from erbium in tellurite glasses is almost twice as broad as the corresponding spectrum in silica. In this presentation, we report the results of a two-prong investigation of new tellurite glasses: a Raman study that provides detail information on the microscopic structure of these glasses, and a study of the erbium emission in fibers fabricated from these glasses. Specifically, we report on the emission from fibers of different lengths and for different pumping schemes.

A-Si:H/a-SiO x:H microcavities with a-Si(Er):H active layer

Fabry–Perot a-Si:H/a-SiO x :H and a-Si(P):H/SnO x microcavities (MCs) with Er-doped a-Si:H active regions were fabricated by plasma-enhanced chemical vapor deposition. A metalorganic compound was used to incorporate erbium into the active a-Si:H layer. The room temperature transmission, reflection and spontaneous emission spectra of the MCs with two and three pairs of layers in distributed Bragg reflectors were measured. An intensity enhancement by two order of magnitude and selective narrowing of the 1.54 μm erbium emission line were observed as compared to the case of a single a-Si(Er):H film deposited on a quartz substrate. A theoretical analysis of the experimental data is given.

Fabry-Perot a-Si:H/a-SiOx:H microcavities with an erbium-doped a-Si:H active layer

Fabry-Perot microcavities tuned to a wavelength of 1.5 µm have been fabricated by means of plasma-enhanced chemical-vapor deposition on the basis of a-Si:H and a-SiOx:H. Distributed Bragg reflectors (DBRs) and the active layer were grown in a single technological cycle. The half-wave active layer was doped with erbium in the course of growth from a metal-organic compound. The high optical contrast enabled a high microcavity quality factor (Q=355) with only three DBR periods. The intensity of erbium photoluminescence (PL) from the microcavity is two orders of magnitude higher than that of erbium emission from an identical a-Si:H layer without DBR. Transmission, reflection, and PL spectra are analyzed. It is found that the spectral shape of the line of erbium PL (transition 4 I 13/2 → 4 I 15/2) from the microcavity virtually coincides with the shape of the resonance peak of its transmission spectrum. Theoretical calculations have been performed providing a comprehensive description of the observed experimental spectra.

Infrared LEDs and microcavities based on erbium-doped silicon nanocomposites

We demonstrate stable room-temperature electroluminescence at 1.54 μm under both forward and reverse bias conditions from erbium-doped silicon nanocomposites. We also show enhanced and tunable emission from erbium when incorporated in porous silicon based microcavities. Erbium is infiltrated in the pores by cathodic electrochemical migration of the ions followed by high temperature annealing (600–1100°C) to produce a composite material made of silicon nanocrystals and silicon dioxide. The devices exhibit an exponential electroluminescence dependence in both bias conditions as a function of the driving current and driving voltage. In reverse bias, the external quantum efficiency reaches 0.01%. The devices show a large temperature dependence of the electroluminescence intensity. The electroluminescence intensity decreases by a factor of 24 in reverse bias and 2.6 in forward bias when the temperature increases from 240 to 300 K. The photoluminescence from the erbium-doped microcavity resonators is enhanced by more than one order of magnitude and tuned to emit in areas where the natural erbium emission is very weak.

Effect of dislocations on the photoluminescence decay of 1.54 μm emission from erbium-doped silicon

The decay of the photoluminescence at 1.54 μm from erbium-implanted silicon has been recorded over nearly three decades of intensity. Two components of the decay are observed at 7.5 K, one with a decay time constant of ∼40–160 μs, and the other with a characteristic time of between 800 and 1200 μs. It is found that the proportions of fast and slow components can vary depending upon the amount of implantation-induced damage, and this variation correlates with a broadening on the high energy side of the erbium related emission. The temperature dependence of the fastest decay is not consistent with it being due to an Auger process involving free carriers, and it is suggested that extended defects in the layers are responsible for this part of the decay curve. The broadening of the erbium line is attributed to the overlap of the dislocation-related line D1 with the erbium emission. Selective chemical etching and scanning electron microscopy show that there are extended defects present in samples with a short fast decay component.

Erbium emission from porous silicon one-dimensional photonic band gap structures

We report tunable, narrow, directional, and enhanced erbium emission from one-dimensional photonic band gap structures. The structures are prepared by anodic etching of crystalline silicon and consist of two highly reflecting porous silicon Bragg reflectors sandwiching an active layer. The cavities are doped by cathodic electromigration of the erbium ions into the porous silicon matrix, followed by high temperature oxidation. By controlling the oxidation temperature of the structure, the position of the erbium emission near 1.5 μm is tuned to regions where the natural erbium spectrum is very weak. The erbium emission from the cavity is narrowed to a full width at half maximum of 12 nm with a quality factor Q of 130, highly directional with a 20° emission cone around the normal axis, and enhanced by more than one order of magnitude.

Erbium Emission from Silicon Based Photonic Bandgap Materials

AbstractControl over the 1.5 µm emission from erbium is desirable for communication and computational technologies because the erbium emission falls in the window of maximum transmission for silica based fiber optics. Tunable, narrow, directional, and enhanced erbium emission from silicon based 1-D photonic bandgap structures will be demonstrated. The structures are prepared by anodic etching of crystalline silicon and consist of two highly reflecting Bragg reflectors sandwiching an active layer. The cavities are doped by electro-migrating the erbium ions into the porous silicon matrix, followed by high temperature oxidation. By controlling the oxidation temperature, porosity, and thickness of the structure, the position of the erbium emission is tuned to emit in regions where the normal erbium emission is very weak. The erbium emission from the cavity is narrowed to a full width at half maximum (FWHM) of 12 nm with a cavity quality factor Q of 130, highly directional with a 20 degree emission cone around the normal axis, and enhanced by more than one order of magnitude when compared to its lateral emission. Erbium photoluminescence (PL) from porous silicon 2-D photonic bandgap structures is also demonstrated.

Room-temperature photoluminescence excitation spectroscopy of Er3+ ions in Er- and (Er+Yb)-doped SiO2 films

We apply photoluminescence excitation spectroscopy to study the efficiency of excitation at 960–990 nm of the 1.54 μm emission of erbium implanted into SiO2 films thermally grown on silicon for a range of Er and Yb concentrations. We show that, in silica films doped solely with Er, the concentration of Er should be lower than 1020 cm−3 to prevent efficient concentration quenching of the emission. It is shown that the Yb/Er concentration ratio of 1–2 is optimum for the dopant densities of 1–2×1020 cm−3, whereas 1021 cm−3 results in quenching of the emission due to energy losses within the Yb subsystem.

Characteristics of surface and waveguide emitting SiGe : Er : O diodes

In this paper we demonstrate electroluminescence from erbium- and oxygen doped Si and SiGe diodes in surface emitting and waveguiding geometry. The layers were deposited by molecular beam epitaxy (MBE) on (1 0 0)Si. A series of samples with varying Er : O-doped layer thickness was grown, showing a decrease in luminescence intensity for layers thinner than 80 nm. The current–voltage characteristics and luminescence properties of another series of samples with varying Ge content were examined. They are probably influenced by strain relaxation at large Ge content. Si/SiGe waveguides were processed and their emission was analyzed by a confocal microscope setup. The spatially narrow emission and the dependence of luminescence on waveguide length proved optical guiding of the erbium emission.

Optical absorption of in and

The optical absorption of in (RTP) and (KTP) single crystals has been characterized at 5 K and 300 K temperatures. The room temperature oscillator strengths of obtained in both lattices are similar although in KTP the uncertainty is higher due to the lower concentration of Er in the samples available. The results obtained in RTP have been analysed by using the Judd-Ofelt theory. The effective Judd-Ofelt parameters obtained for in RTP are , , . The photoluminescence transition radiative rates, branching ratios and radiative lifetimes of in these crystals have been calculated for all de-excitations from the multiplet. The erbium emission has been characterized. The low temperature optical absorption and photoluminescence suggest the coexistence of two erbium centres in both lattices, which we have tentatively ascribed to the occupancy with different population densities of the two titanium lattice sites.

Room temperature 1.54 μm light emission of erbium doped Si Schottky diodes prepared by molecular beam epitaxy

Schottky-type light emitting devices have been fabricated on Er-oxide doped Si layers grown by molecular beam epitaxy, in order to study the light emission process of Er-doped Si structures. By applying a reverse bias on the Schottky junction, Er ions incorporated within the depletion layer can be electrically excited via a hot electron impact process. Rather intense electroluminescence (EL) at a wavelength of 1.54 μm has been observed at room temperature. The optoelectronic properties of the devices have been characterized by both input-power dependent and temperature dependent EL measurements. An activation energy value of ∼160 meV responsible for luminescence thermal quenching has been obtained.

Laser induced breakdown spectroscopy (LIBS) as an analytical tool for the detection of metal ions in aqueous solutions.

Laser induced breakdown spectroscopy (LIBS) is applied to analyze aqueous solutions of Li(+), Na(+), Ca(2+), Ba(2+), Pb(2+), Cd(2+), Hg(2+) and Er(3+) and suspensions of ErBa(2)Cu(3)O(x) particles (d=0.2 microm). An excimer (308 nm) pumped dye laser with laser pulse at 500 nm and pulse energy at 22+/-2 mJ is used to produce plasma in aqueous solution. Plasma emission lines of the elements are detected by a photodiode array detector. Detection limits of the metal ions are 500 mg/l for Cd(2+), 12.5 mg/l for Pb(2+), 6.8 mg/l for Ba(2+), 0.13 mg/l for Ca(2+), 13 microg/l for Li(+) and 7.5 microg/l for Na(+). No mercury and erbium emission can be detected, even at Hg(2+) and Er(3+) concentrations of up to the g/l range. On the other side, for Er in suspensions of ErBa(2)Cu(3)O(x) particles a more than 10(3) times higher sensitivity is found than for dissolved Er(3+). This result gives a possibility to analyze colloid-borne metal ions with an increased sensitivity.

Photoluminescence of Sige Alloys Implanted with Erbium

AbstractThe 1.54μm emission of erbium implanted SiGe alloys was investigated as a function of oxygen and germanium concentrations as well as defect densities. Samples of SiGe layers grown by atmospheric pressure chemical vapor deposition technique which contain high concentrations of grown-in oxygen in the 10 19 - 1020 cm−3 range and 2 - 24 % Ge were chosen for the experiments. By using rapid thermal annealing in nitrogen atmosphere, a high optical activation of Er was found by photoluminescence. In samples with low defect densities nearly one third of the implanted Er ion dose could be detected in form of electrically active donors by spreading resistance measurements. The behavior of different SiGe : Er layers, based on sample property and annealing condition, suggests that more than only one type of luminescent Er-complex is present.

A Composite Layer of Al‐Er‐O Particles in a Silicon Matrix

Erbium is of particular interest in telecommunication systems because of its sharp and intense photoemission at 1.54 μm. However, erbium is difficult to incorporate at high concentrations in the semiconductor matrix and presents a tendency to segregate in the material. A better solution would be to use the erbium impurity as an element of the matrix rather than as a dopant. Such a structure can be obtained with a garnet‐like layer realized on a semiconductor substrate. Evaporation, implantation, and annealing techniques were combined to obtain a new ternary material Al‐Er‐O. These garnet‐like layers were developed on silicon. The layer composition as well as the interaction of the different elements with the substrate were studied by Rutherford backscattering, secondary ion mass spectroscopy, and X analyses. The surface aspect variations were observed by scanning electron microscopy. According to the annealing conditions, a photoluminescence at about 1.54 μm corresponding to erbium emission was observed at 77 K. This luminescence is due to insulating microparticles composed of aluminum, erbium, oxygen, and possibly silicon.

Photoluminescence properties of Cr:Er:GGG

An analysis of the photoluminescence properties of Cr:Er:GGG indicates that the erbium emission at 1.6 μm and 2.8 μm can be efficiently sensitized by a chromium co-doping. Increasing the erbium concentration enhances the 2.8 μm emission, while the 1.6 μm emission decreases. This effect is due to a cooperative upconversion of two erbium ions in the 4I 13/2 state. The lifetime of the 2.8 μm emission in Cr:Er:GGG is 1.3 ms which is about an order of magnitude longer than in Er:YAG.

Enhanced 1.54 μm emission of erbium implanted silicon

A new way of overcoming the limited solid solubility of erbium in crystalline silicon, which severely affects the luminescence efficiency of erbium implanted materials, is reported. The enhanced 1.54 μm emission of Er 3+ in Si is obtained from samples using erbium implanted into a silicon-on-insulator structure.

Behaviour of erbium implanted in InP

Erbium impurities were implanted in indium phosphide. The 2 K, 77 K and 300 K photoluminescence spectra show, after annealing at high temperature, the main erbium emission centered at 1.536μm. The variation of this Er-peak luminescence is studied as a function of the implanted dose, the annealing temperature and the annealing duration.

Nondiffusion and 1.54/μm luminescence of erbium implanted in InP

Erbium impurities were implanted in indium phosphide. The Er depth distributions are given for nonannealed and annealed substrates. It is shown that erbium has a very small diffusion coefficient, if any, in InP. The photoluminescence spectra show, after annealing at high temperature, the main erbium emission centred at 1.536μm. This emission is stronger after annealing at 700°C. Our results are the first evidence showing l.54μm emission at room temperature.

Quenching factors in the anti-Stokes emission of holmium and erbium doped yttrium oxysulphide phosphors

Traces of dysprosium quench the Stokes and anti-Stokes emissions, the latter more strongly, of 1 μm excited holmium and erbium, ytterbium doped Y2O2S phosphors. Infrared emission of Dy3+ shows strong self-quenching. Anti-Stokes emission of holmium is very efficient at low temperatures but a thermally activated back transfer of the second stage excitation causes poor efficiency at ambient temperatures. Traces of holmium in erbium doped phosphors enhance the anti-Stokes red emission of erbium in a controllable way.