Photoluminescence of Erbium Implanted in SiGe

1996 ◽  
Vol 422 ◽  
Author(s):  
S. J. Chang ◽  
D. K. Nayak ◽  
Y Shiraki
Keyword(s):  
Activation Energy ◽  
Optical Properties ◽  
High Temperatures ◽  
Room Temperature ◽  
Luminescence Centers ◽  
Pl Intensity ◽  
Er Doped

The optical properties of an Er-implanted SiGe sample have been studied Sharp and temperature-stable Er-related PL peaks were observed at around 1.5pm, which correspond to the Er 4I13/2 to 4I15/2 transition. It was found that the Er ions form more than three noncubic luminescence centers in the SiGe host. Although the PL intensity quenches at high temperatures, the Errelated PL signal can still be observed at room temperature. For a Si0.87Ge0.13:Er sample annealed at 850°C for 20 min, the activation energy is 130 meVwhich is slightly smaller than that of the Er-doped Si.

Doping of GaN by ion implantation

2000 ◽  
Vol 650 ◽  
Author(s):  
Eduardo J. Alves ◽  
C. Liu ◽  
Maria F. da Silva ◽  
José C. Soares ◽  
Rosário Correia ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ion Implantation ◽  
Room Temperature ◽  
Lattice Site ◽  
Helium Temperature ◽  
Site Location ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Er Doped ◽  
Ion Implanted

ABSTRACTIn this work we report the structural and optical properties of ion implanted GaN. Potential acceptors such as Ca and Er were used as dopants. Ion implantation was carried out with the substrate at room temperature and 550 °C, respectively. The lattice site location of the dopants was studied by Rutherford backscattering/channeling combined with particle induced X-ray emission. Angular scans along both [0001] and [1011] directions show that 50% of the Er ions implanted at 550 oC occupy substitutional or near substitutional Ga sites after annealing. For Ca we found only a fraction of 30% located in displaced Ga sites along the [0001] direction. The optical properties of the ion implanted GaN films have been studied by photoluminescence measurements. Er- related luminescence near 1.54 μm is observed under below band gap excitation at liquid helium temperature. The spectra of the annealed samples consist of multiline structures with the sharpest lines found in GaN until now. The green and red emissions were also observed in the Er doped samples after annealing.

Doping of GaN by ion implantation

2000 ◽  
Vol 647 ◽  
Author(s):  
Eduardo J. Alves ◽  
C. Liu ◽  
Maria F. da Silva ◽  
José C. Soares ◽  
Rosário Correia ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ion Implantation ◽  
Room Temperature ◽  
Lattice Site ◽  
Helium Temperature ◽  
Site Location ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Er Doped ◽  
Ion Implanted

AbstractIn this work we report the structural and optical properties of ion implanted GaN. Potential acceptors such as Ca and Er were used as dopants. Ion implantation was carried out with the substrate at room temperature and 550 °C, respectively. The lattice site location of the dopants was studied by Rutherford backscattering/channeling combined with particle induced X-ray emission. Angular scans along both [0001] and [1011] directions show that 50% of the Er ions implanted at 550 °C occupy substitutional or near substitutional Ga sites after annealing. For Ca we found only a fraction of 30% located in displaced Ga sites along the [0001] direction. The optical properties of the ion implanted GaN films have been studied by photoluminescence measurements. Er- related luminescence near 1.54 µm is observed under below band gap excitation at liquid helium temperature. The spectra of the annealed samples consist of multiline structures with the sharpest lines found in GaN until now. The green and red emissions were also observed in the Er doped samples after annealing.

Influence of Er and O doses in Er-related emission in Al0.70Ga0.30As:Er

2001 ◽  
Vol 692 ◽  
Author(s):  
Shin-ichiro Uekusa ◽  
Tomoyuki Arai
Keyword(s):  
Activation Energy ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Thermal Quenching ◽  
Activation Energies ◽  
Optimum Dose ◽  
Radiative Efficiency ◽  
Gaas Substrates ◽  
Pl Intensity

AbstractEr ions with doses ranging from 1×1013 cm−2 to 1×1015 cm−2 were implanted into Al0.70Ga0.30As on GaAs substrates. at 800 °C. Photoluminescence (PL) intensity of Er-related emission around 1.54 μm was enhanced by co-implanted oxygen (O). The optimum dose of Er ion was 1×1014 cm−2 and O ion was 1×1015 cm−2, respectively. Furthermore, from the temperature dependence of the PL intensity of sample implanted with the optimum dose, we estimated the values of E1, E2, and E3, the activation energies in order to investigate the rapid thermal quenching of Er ion in Al0.70Ga0.30As. We found that PL intensity of Er-related emission, in addition to O dose, was enhanced approximately twenty two times at room temperature. And from the temperature dependence of the lifetime of the optimum dose of Er and O, the value 245meV of EA, the activation energy for the decrease of the lifetime, was nearly equal to the value 235meV of E3. Based on the result, the decrease of the lifetime confirms that the radiative efficiency is lower; therefore, we propose that rapid thermal quenching occurs at temperatures above 200 K due to the decrease of the radiative efficiency.

Influence of In0.2Ga0.8As strain-reducing layer on the active region of quantum dot superluminescent diodes

2002 ◽  
Vol 737 ◽  
Author(s):  
Z. Y. Zhang ◽  
Ch. M. Li ◽  
P. Jin ◽  
X. Q. Meng ◽  
B. Xu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Active Region ◽  
Quantum Dot ◽  
Room Temperature ◽  
Spectral Width ◽  
Promising Candidate ◽  
Multiple Layer ◽  
Superluminescent Diodes ◽  
Pl Intensity ◽  
Inas Quantum Dot

ABSTRACTWe have investigated the optical properties of asymmetric multiple layer stacked self-assembled InAs quantum dot with different interlayer. We found that asymmetric multiple stacked QD samples with In0.2Ga0.8As + GaAs interlayer can afford a 180nm flat spectral width with strong PL intensity compared to other samples at room temperature. We think this result is due to the introduction of In0.2Ga0.8As strain-reducing layer. Additionally, for the broad spectral width and the strong PL intensity, this structure can be a promising candidate for quantum-dot superluminescent diodes.

Room-Temperature Photoluminescence Observation of Stacking Faults in 3C-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 355-358 ◽  
Author(s):  
Rii Hirano ◽  
Michio Tajima ◽  
Kohei M. Itoh
Keyword(s):  
Silicon Carbide ◽  
Optical Properties ◽  
Room Temperature ◽  
Stacking Faults ◽  
Room Temperature Photoluminescence ◽  
Pl Spectra ◽  
Intensity Mapping ◽  
Pl Mapping ◽  
Pl Intensity ◽  
Cubic Silicon Carbide

We investigated the optical properties of stacking faults (SFs) in cubic silicon carbide by photoluminescence (PL) spectroscopy and mapping. The room-temperature PL spectra consisted of a 2.3 eV peak due to nitrogen and two undefined broad peaks at 1.7 eV and 0.95 eV. On the PL intensity mapping for the 2.3 eV peak, SFs appeared as dark lines. SFs which expose carbon atoms (SFC) and silicon atoms (SFSi) on the surface appeared as bright lines and dark lines, respectively, in PL mapping for the 1.7 eV and 0.95 eV peaks. We believe the two undefined peaks are associated with SFC. This technique allows us to detect SFs nondestructively and to distinguish between SFC and SFSi. We further suggest the presence of inhomogeneous stress around SFCs based on the broadening of the 2.3 eV peak.

High Temperature n- and p-type Doped Microcrystalline Silicon Layers Grown by VHF PECVD Layer-by-Layer Deposition

2003 ◽  
Vol 762 ◽  
Author(s):  
A. Gordijn ◽  
J.K. Rath ◽  
R.E.I. Schropp
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
High Temperatures ◽  
Continuous Wave ◽  
Hydrogen Plasma ◽  
Silicon Layer ◽  
Dark Conductivity ◽  
High Deposition Rate ◽  
Layer By Layer ◽  
Microcrystalline Silicon

AbstractDue to the high temperatures used for high deposition rate microcrystalline (μc-Si:H) and polycrystalline silicon, there is a need for compact and temperature-stable doped layers. In this study we report on films grown by the layer-by-layer method (LbL) using VHF PECVD. Growth of an amorphous silicon layer is alternated by a hydrogen plasma treatment. In LbL, the surface reactions are separated time-wise from the nucleation in the bulk. We observed that it is possible to incorporate dopant atoms in the layer, without disturbing the nucleation. Even at high substrate temperatures (up to 400°C) doped layers can be made microcrystalline. At these temperatures, in the continuous wave case, crystallinity is hindered, which is generally attributed to the out-diffusion of hydrogen from the surface and the presence of impurities (dopants).We observe that the parameter window for the treatment time for p-layers is smaller compared to n-layers. Moreover we observe that for high temperatures, the nucleation of p-layers is more adversely affected than for n-layers. Thin, doped layers have been structurally, optically and electrically characterized. The best n-layer made at 400°C, with a thickness of only 31 nm, had an activation energy of 0.056 eV and a dark conductivity of 2.7 S/cm, while the best p-layer made at 350°C, with a thickness of 29 nm, had an activation energy of 0.11 V and a dark conductivity of 0.1 S/cm. The suitability of these high temperature n-layers has been demonstrated in an n-i-p microcrystalline silicon solar cell with an unoptimized μc-Si:H i-layer deposited at 250°C and without buffer. The Voc of the cell is 0.48 V and the fill factor is 70 %.

Degradation in a Methyl-phenyl Co-Polymeric Polysilane for LED Applications

2003 ◽  
Vol 769 ◽  
Author(s):  
Asha Sharma ◽  
Deepak ◽  
Monica Katiyar ◽  
Satyendra Kumar ◽  
V. Chandrasekhar ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Weight ◽  
Light Source ◽  
Room Temperature ◽  
Light Exposure ◽  
Room Temperature Photoluminescence ◽  
Pl Spectrum ◽  
Pl Intensity ◽  
Methyl Phenyl

AbstractThe optical degradation of polysilane copolymer has been studied in spin cast thin films and solutions using light source of 325 nm wavelength. The room temperature photoluminescence (PL) spectrum of these films show a sharp emission at 368 nm when excited with a source of 325 nm. However, the PL intensity deteriorates with time upon light exposure. Further the causes of this degradation have been examined by characterizing the material for its transmission behaviour and changes occurring in molecular weight as analysed by GPC data.

scholarly journals Polymorphic gallium for active resonance tuning in photonic nanostructures: from bulk gallium to two-dimensional (2D) gallenene

Nanophotonics ◽  
2020 ◽  
Vol 9 (14) ◽  
pp. 4233-4252
Author(s):  
Yael Gutiérrez ◽  
Pablo García-Fernández ◽  
Javier Junquera ◽  
April S. Brown ◽  
Fernando Moreno ◽  
...  
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Phase Change Materials ◽  
Two Dimensional ◽  
Active Materials ◽  
Promising Candidate ◽  
Plasmonic Structures ◽  
Resonance Tuning ◽  
The Many ◽  
Optical Behavior

AbstractReconfigurable plasmonics is driving an extensive quest for active materials that can support a controllable modulation of their optical properties for dynamically tunable plasmonic structures. Here, polymorphic gallium (Ga) is demonstrated to be a very promising candidate for adaptive plasmonics and reconfigurable photonics applications. The Ga sp-metal is widely known as a liquid metal at room temperature. In addition to the many other compelling attributes of nanostructured Ga, including minimal oxidation and biocompatibility, its six phases have varying degrees of metallic character, providing a wide gamut of electrical conductivity and optical behavior tunability. Here, the dielectric function of the several Ga phases is introduced and correlated with their respective electronic structures. The key conditions for optimal optical modulation and switching for each Ga phase are evaluated. Additionally, we provide a comparison of Ga with other more common phase-change materials, showing better performance of Ga at optical frequencies. Furthermore, we first report, to the best of our knowledge, the optical properties of liquid Ga in the terahertz (THz) range showing its broad plasmonic tunability from ultraviolet to visible-infrared and down to the THz regime. Finally, we provide both computational and experimental evidence of extension of Ga polymorphism to bidimensional two-dimensional (2D) gallenene, paving the way to new bidimensional reconfigurable plasmonic platforms.

On the use of Ozawa/Flynn/Wall method to determine aging activation energy for elastomers

2021 ◽  
pp. 009524432110203
Author(s):  
Sudhir Bafna
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Weight Loss ◽  
Oxygen Consumption ◽  
Dwell Time ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Degradation Mechanism ◽  
Kinetics Of ◽  
Wall Method

It is often necessary to assess the effect of aging at room temperature over years/decades for hardware containing elastomeric components such as oring seals or shock isolators. In order to determine this effect, accelerated oven aging at elevated temperatures is pursued. When doing so, it is vital that the degradation mechanism still be representative of that prevalent at room temperature. This places an upper limit on the elevated oven temperature, which in turn, increases the dwell time in the oven. As a result, the oven dwell time can run into months, if not years, something that is not realistically feasible due to resource/schedule constraints in industry. Measuring activation energy (Ea) of elastomer aging by test methods such as tensile strength or elongation, compression set, modulus, oxygen consumption, etc. is expensive and time consuming. Use of kinetics of weight loss by ThermoGravimetric Analysis (TGA) using the Ozawa/Flynn/Wall method per ASTM E1641 is an attractive option (especially due to the availability of commercial instrumentation with software to make the required measurements and calculations) and is widely used. There is no fundamental scientific reason why the kinetics of weight loss at elevated temperatures should correlate to the kinetics of loss of mechanical properties over years/decades at room temperature. Ea obtained by high temperature weight loss is almost always significantly higher than that obtained by measurements of mechanical properties or oxygen consumption over extended periods at much lower temperatures. In this paper, data on five different elastomer types (butyl, nitrile, EPDM, polychloroprene and fluorocarbon) are presented to prove that point. Thus, use of Ea determined by weight loss by TGA tends to give unrealistically high values, which in turn, will lead to incorrectly high predictions of storage life at room temperature.

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