Strong 1.54 μm luminescence from erbium-doped porous silicon (original) (raw)
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Excitation mechanisms and localization sites of erbium-doped porous silicon
Applied Surface Science, 2006
Porous silicon (PS) is doped with erbium by electrochemical anodisation. The penetration of erbium into the PS layer is confirmed by Rutherford backscattering spectroscopy (RBS) and energy dispersive X-ray (EDX) measurements. Efficient green and infrared emissions were observed at room temperature. The investigations are focused on the evolutions versus temperature and pump intensity of the green photoluminescence (PL) corresponding to the 4 S 3/2 ! 4 I 15/2 transition. It was found that an erbium related level defect can be involved on the excitation and emission processes of erbium. Pump intensity dependent PL studies revealed that for the electrochemical incorporation, most of the Er 3+ ions are localized inside the Si nanocrystallites and not in stoichiometric SiO 2 . The optical cross-section is close to that of erbium in Si nanocrystallites. #
MRS Proceedings
The present work is concerned with Er-doped oxidized porous silicon (PS). The characteristic feature of the work is that PS doping has been realized by an electrochemical procedure followed by a high temperature treatment. 5-μm thick PS layers were formed on p-type Si of 0.3-Ohm-cm resistivity. Er incorporation was performed by a cathodic polarization of PS in a 0.1 M Er(NO3)3 aqueous solution. A high temperature treatment in an oxidizing ambient at 500-1000°C was utilized to provide either partial or total oxidation of PS:Er layers. X-ray microanalysis was used to study chemical composition of the samples. Photoluminescence (PL) and photoluminescence excitation (PLE) spectra were investigated. After the partial oxidation (in the temperature range of 600-800°C), weak Er3+-related PL at 1.53 ptm was observed. A high temperature anneal in Ar atmosphere at the temperature of 1100°C caused a significant increase in the Er3+-related PL intensity. Resonant features were observed in PLE sp...
Photoluminescence from erbium incorporated in oxidized porous silicon
Optical Materials, 2005
In the present work, photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy were used to study oxidized porous silicon (OPS) doped with Er by electrochemical migration. Three types of OPS were investigated: (a) partially oxidized PS (POPS); (b) fully oxidized PS (FOPS); (c) oxidized PS co-doped with Fe (OPS:Fe). The OPS consists of oxide, Si nanoclusters and voids, and their composing fractions are dependent on the PS porosity and oxidation regime. The main result of this work is the assessment that the location of Er ions in composing fractions of OPS has a profound effect on the PL and PLE spectra. We show that for both POPS and FOPS, Er exhibits a broad 1530 nm PL spectrum similar to that observed in the Er-doped silica glasses. For POPS, the PLE spectrum of the 1530 nm Er PL band consists of a superposition of sharp peaks, which are attributed to the absorption transitions of Er ions incorporated into the oxide fraction, and a broad band, which is related to the absorption band of Si nanoclusters. For FOPS, the PLE spectrum consists just of sharp peaks. In contrast to POPS and FOPS, for OPS:Fe, Er PL spectrum consists of 21 highly resolved peaks. PLE spectrum of the strongest 1535 nm PL peak represents a wide band which is attributed to the absorption band of Fe:O nanoclusters formed inside OPS:Fe. Mechanism of excitation and luminescence of Er ions in OPS is presented.
Stable photoluminescence and electroluminescence from porous silicon
Thin Solid Films, 1997
By carefully controling the nanocrystallite surface passivation, it is possible to make light-emitting porous silicon essentially inert and to stabilize its photoluminescence. Using this material, which we call silicon-rich silicon oxide (SRSO), stable and efficient porous silicon lightemitting devices (LEDs) emitting in the visible have been manufactured. The material's optimization, device design, and device fabrication that have allowed us to achieve these goals are discussed. The electrical and optical properties of the LEDs are described and explained by a model for carrier transport and recombination. By changing the preparation and processing conditions and by doping the SRSO layer with impurities such as erbium, photoluminescence and electroluminescence at longer wavelengths have been demonstrated. q 1997 Elsevier Science S.A.
Journal of Luminescence, 2000
Sites of the Er> luminescent centers in Er-doped porous silicon (PS : Er) formed by immersion are studied in order to make clear the cause of the strong room temperature luminescence at 1.54 m due to the 4f intra-transition of Er> ions. The luminescence spectra and the temperature quenching of the intensity and the #uorescence lifetime are compared between PS : Er samples formed by immersion in an ErCl /alcohol solution and Er-implanted PS, using the same PS hosts. PS : Er samples formed by immersion show a small temperature quenching in the intensity and the #uorescence lifetime, resulting in a strong luminescence at RT. On the other hand, PS : Er samples formed by Er ion implantation into PS shows almost the same strong temperature quenching as the Er-implanted crystalline Si. These results indicate that the sites of Er ions responsible for the strong RT 1.54 m luminescence in PS : Er formed by immersion is not inside Si nanocrystals but on the surface of Si nanocrystals.
Scientific reports, 2017
Er clustering plays a major role in hindering sufficient optical gain in Er-doped Si materials. For porous Si, the long-standing failure to govern the clustering has been attributed to insufficient knowledge of the several, concomitant and complex processes occurring during the electrochemical Er-doping. We propose here an alternative road to solve the issue: instead of looking for an equilibrium between Er content and light emission using 1-2% Er, we propose to significantly increase the electrochemical doping level to reach the filling the porous silicon pores with luminescent Er-rich material. To better understand the intricate and superposing phenomena of this process, we exploit an original approach based on needle electron tomography, EXAFS and photoluminescence. Needle electron tomography surprisingly shows a heterogeneous distribution of Er content in the silicon thin pores that until now couldn't be revealed by the sole use of scanning electron microscopy compositional ...
Porous silicon: material properties, visible photo- and electroluminescence
Applied Surface Science, 1993
Following the recent discovery of visible photo and electroluminescence of high-porosity porous silicon layers this paper presents a review of the most relevant results and models proposed to explain the phenomena. Porous silicon fabrication techniques are presented including some recommendations to allow a meaningful comparison of results obtained hy different laboratories. Recent results of pore size. surface area measurements. crystallographic structure determination and microstructure observations are discussed. Detailed studies of optical absorption coefficients of porous layers of different porosities are pt-esentetf. A clear upshift toward the visible range is explained by a quantum confinement model. Intense visible photoluminesccnce ol porous silicon layers is discussed on the ground of both quantum confinement and surface-controlled phenomena. The caaential role played by surface passivation, for efficient luminescence. is analysed. Reported results of visible electroluminescence during anodic oxidation of porous silicon layers and visible light emission from solid-state porous silicon dcviccs are reviewed.
Porous silicon as low-dimensional host material for erbium-doped structures
Thin Solid Films, 1997
A low-dimensional matrix of porous silicon (PS) was found to be an effective host material for erbium (Er) electrodeposition from Er(NO 3) 3 P5H 2 O/ethanol solution. After thermal annealing at 850-1200 8C in an O 2-containing atmosphere, such material exhibited sharp 1.54 mm luminescence at 77 K and 300 K. In contrast to previous studies, strong Er-related photoluminescence (PL) was found not only in the case of red-emitting PS formed in initial p-Si(111) wafers of 0.3 V cm resistivity but also for micro-sized material formed in initial 0.01 V cm n q-Si(111). Erbium doping of p-type PS resulted in a 1.54 mm peak appearance in addition to two broad PL bands at about 1.3 mm and 0.8-0.9 mm. In contrast, n q-type PS:Er exhibited only a sharp 1.54 mm peak without other PL bands. The intensity of the Er-related peak depended strongly on the Si anodization regime and increased with the PS thickness growth from 1 to 20 mm. Application aspects of PS:Er for light-emitting devices and integrated optical waveguides are discussed. q 1997 Elsevier Science S.A.
Journal of Luminescence, 1998
O films containing about 10 wt% of Er O were deposited on porous silicon by dipping or by a spin-on technique followed by thermal processing at 1073 K for 15 min. The samples were characterized by means of PL, SEM and X-ray diffraction analyses. They exhibit strong room-temperature luminescence at 1.5 m related to erbium in the sol-gel derived host. The luminescence intensity increases by a factor of 1000 when the samples are cooled from 300 to 4.2 K. After complete removal of the erbium-doped film by etching and partial etching the porous silicon, the erbium-related luminescence disappears. Following this, luminescence at 1.5 m originating from optically active dislocations ("D-lines") in porous silicon was detected. The influence of the conditions of synthesis on luminescence at 1.5 m is discussed.