Lattice Location and Cathodoluminescence Studies of Ytterbium/Thulium Implanted 2H-Aluminium Nitride

2002 ◽  
Vol 743 ◽  
Author(s):  
U. Vetter ◽  
M. F. Reid ◽  
H. Hofsäss ◽  
C. Ronning ◽  
J. Zenneck ◽  
...  
Keyword(s):  
Room Temperature ◽  
Lattice Site ◽  
Electron Transition ◽  
Lattice Location ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Annealing Temperatures ◽  
Visible Luminescence ◽  
On Line ◽  
Emission Channeling

ABSTRACTLattice location studies of radioactive 169Yb ions, implanted at an energy of 60 keV into 2H-AlN at the on-line isotope separator ISOLDE at CERN, were performed using the emission channeling technique. The measurements, which yield a substitutional Al lattice site for the implanted ions, were recorded for annealing temperatures ranging from 293 K to 1273 K. After complete decay of 169Yb to 169Tm cathodoluminescence measurements were performed in the range 12 K – 300 K. The samples show a strong visible luminescence at 460 - 470 nm at room temperature, which is attributed to the 1D2−3F4 intra-4f electron transition of Tm3+. At 12 K the luminescence is dominated by transitions starting from the 1H6 multiplet. Time resolved as well as temperature dependent cathodoluminescence measurements are presented and discussed.The lattice location as well as the time resolved cathodoluminescence measurements suggest that there is only one pronounced site of the implanted ions in the AlN lattice and that this is the substitutional aluminium site.

Lattice Location and Luminescence Behavior of Rare Earth Elements Implanted in GaN

1997 ◽  
Vol 482 ◽  
Author(s):  
M. Dalmer ◽  
M. Restle ◽  
A. Stötzler ◽  
U. Vetter ◽  
H. Hofsäss ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Room Temperature ◽  
Lattice Location ◽  
Isochronal Annealing ◽  
Line Intensities ◽  
Order Of Magnitude ◽  
Photoluminescence Studies ◽  
Luminescence Behavior ◽  
Emission Channeling

AbstractSingle crystalline GaN-layers were implanted with radioactive 167Tm and 169yb ions, and their lattice sites were determined using the emission channeling technique. After the decay of 167Tm to 167Er, photoluminescence studies were performed. Upon room temperature implantation, rare earth atoms immediately occupy relaxed substitutional sites with an average relaxation of about 0.025 nm. Isochronal annealing treatments up to 800 °C and co-implantation of oxygen to a dose an order of magnitude greater than that of the Tm or Yb do not influence the rare earth lattice sites. A variety of different rare earth related luminescence lines are observed, and co-implantation of oxygen strongly changes the line intensities.

scholarly journals Optical Spectroscopy of Ingan Epilayers in the Low Indium Composition Regime

1999 ◽  
Vol 595 ◽  
Author(s):  
M. H. Crawford ◽  
J. Han ◽  
M. A. Banas ◽  
S. M. Myers ◽  
G. A. Petersen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Radiative Decay ◽  
Thermal Quenching ◽  
Localized States ◽  
Spectral Variation ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Decay Times ◽  
Integrated Intensity ◽  
Si Doped

AbstractPhotoluminescence (PL) spectroscopy was carried out on a series of Si-doped bulk InGaN films in the low indium (In) composition regime. Room temperature PL showed a factor of 25 increase in integrated intensity as the In composition was increased from 0 to 0.07. Temperature dependent PL data was fit to an Arrhenius equation to reveal an increasing activation energy for thermal quenching of the PL intensity as the In composition is increased. Time resolved PL measurements revealed that only the sample with highest In ( x=0.07) showed a strong spectral variation in decay time across the T=4K PL resonance, indicative of recombination from localized states at low temperatures. The decay times at room temperature were non-radiatively dominated for all films, and the room temperature (non-radiative) decay times increased with increasing In, from 50-230 psec for x=0-0.07. Our data demonstrate that non-radiative recombination is less effective with increasing In composition.

scholarly journals Arsenic in ZnO and GaN: Substitutional Cation or Anion Sites?

2007 ◽  
Vol 994 ◽  
Author(s):  
Ulrich Wahl ◽  
Joao Guilherme Correia ◽  
Elisabete Rita ◽  
Ana Claudia Marques ◽  
Eduardo Alves ◽  
...  
Keyword(s):  
Lattice Site ◽  
Lattice Location ◽  
Site Preference ◽  
Group V ◽  
Defect Complexes ◽  
High Concentrations ◽  
Type Character ◽  
P Type ◽  
Emission Channeling

AbstractModifying the properties of ZnO and GaN by means of incorporating arsenic impurities is of interest in both of these semiconductors, although for different reasons. In the case of ZnO, the group V element As has been reported in the literature as one of the few p-type dopants in this technologically promising II-VI compound. However, there is an ongoing debate whether the p-type character is due to As simply replacing O atoms or to the formation of more complicated defect complexes, possibly involving As on Zn sites [1]. In the case of GaN, the incorporation of high concentrations of As has been studied with respect to the formation of GaAs(x)N(1-x) alloys and the related modification of the GaN band gap and its luminescence behaviour. It has been suggested that As in GaN is amphoteric, with its lattice site preference depending on the doping character of the material, i.e. mostly substitutional Ga in p-type but also substitutional N in n-type [2].We have determined the lattice location of implanted As in ZnO and GaN by means of conversion electron emission channeling from radioactive 73As. In contrast to what one might expect from its nature as a group V element, we find that As does not occupy substitutional O sites in ZnO but in its large majority substitutional Zn sites [3]. Arsenic in ZnO is thus an interesting example for an impurity in a semiconductor where the major impurity lattice site is determined by atomic size and electronegativity rather than its position in the periodic system. The results are different in the case of As implanted into GaN, where we found roughly half of the implanted As atoms occupying Ga and the other half N sites. The amphoteric character of As therefore certainly plays a role in explaining the extreme difficulties in growing high quality GaAs(x)N(1-x) alloys with values of x above a few percent.A preliminary report will also be given on ongoing emission channeling lattice location experiments using radioactive 124Sb in ZnO and GaN.

scholarly journals Optical Spectroscopy of Ingan Epilayers in the Low Indium Composition Regime

2000 ◽  
Vol 5 (S1) ◽  
pp. 717-724
Author(s):  
M. H. Crawford ◽  
J. Han ◽  
M. A. Banas ◽  
S. M. Myers ◽  
G. A. Petersen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Radiative Decay ◽  
Thermal Quenching ◽  
Localized States ◽  
Spectral Variation ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Decay Times ◽  
Integrated Intensity ◽  
Si Doped

Photoluminescence (PL) spectroscopy was carried out on a series of Si-doped bulk InGaN films in the low indium (In) composition regime. Room temperature PL showed a factor of 25 increase in integrated intensity as the In composition was increased from 0 to 0.07. Temperature dependent PL data was fit to an Arrhenius equation to reveal an increasing activation energy for thermal quenching of the PL intensity as the In composition is increased. Time resolved PL measurements revealed that only the sample with highest In (x=0.07) showed a strong spectral variation in decay time across the T=4K PL resonance, indicative of recombination from localized states at low temperatures. The decay times at room temperature were non-radiatively dominated for all films, and the room temperature (non-radiative) decay times increased with increasing In, from 50-230 psec for x=0-0.07. Our data demonstrate that non-radiative recombination is less effective with increasing In composition.

scholarly journals Lattice location and thermal stability of implanted nickel in silicon studied by on-line emission channeling

2014 ◽  
Vol 115 (2) ◽  
pp. 023504 ◽  
Author(s):  
D. J. Silva ◽  
U. Wahl ◽  
J. G. Correia ◽  
L. M. C. Pereira ◽  
L. M. Amorim ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Line Emission ◽  
Lattice Location ◽  
On Line ◽  
Thermal Stability Of ◽  
Emission Channeling

scholarly journals Minority Carrier Lifetime Measurements on 4H-SiC Epiwafers by Time-Resolved Photoluminescence and Microwave Detected Photoconductivity

2019 ◽  
Vol 963 ◽  
pp. 313-317
Author(s):  
Jan Beyer ◽  
Nadine Schüler ◽  
Jürgen Erlekampf ◽  
Birgit Kallinger ◽  
Patrick Berwian ◽  
...  
Keyword(s):  
Room Temperature ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Temperature Dependent ◽  
Lifetime Measurements ◽  
Time Resolved ◽  
Excess Carrier ◽  
Time Resolved Photoluminescence ◽  
Different Thickness

Temperature dependent microwave detected photoconductivity MDP and time-resolved photoluminescence TRPL were employed to investigate the carrier lifetime in CVD grown 4H-SiC epilayers of different thickness. The minority carrier lifetime may be found from both theMDP and defect PL decay at room temperature for all epilayers, whereas the near bandedge emission (NBE) decay is much faster for thin epilayers (<17 μm) due to the substrate proximity and only follows the minority carrier lifetime for thicker samples at lower excess carrier concentrations.

Visible Photoluminescence of Gas Phase Synthesized Well-Defined Germanium Oxide Nanoparticles

2014 ◽  
Vol 618 ◽  
pp. 28-32 ◽  
Author(s):  
Shang Xu ◽  
Ya Li Nan ◽  
Ling Sun
Keyword(s):  
Room Temperature ◽  
Quantum Confinement Effect ◽  
Wavelength Region ◽  
Size Composition ◽  
Oxide Nanoparticles ◽  
Germanium Oxide ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Time Resolved Photoluminescence ◽  
Photoluminescence Behavior

Substoichiometric germanium oxide nanoparticles were synthesized through gas aggregation process with a careful control on the size, composition and crystallinity of the nanoparticles. The nanoparticles show broad room temperature photoluminescence (PL) in the 470nm to 600nm wavelength region. The microstructure and optical properties of the nanoparticles were investigated. We found that the photoluminescence behavior of the nanoparticles is critically influenced by their compositions. Through temperature-dependent photoluminescence and time-resolved photoluminescence spectroscopy, we concluded that the broad PL band originated from the defects in the GeOx shell layers, rather than the quantum-confinement effect.

Recovery of Structural Defects in GaN After Heavy Ion Implantation

1997 ◽  
Vol 468 ◽  
Author(s):  
C. Running ◽  
M. Dalmer ◽  
M. Deicher ◽  
M. Restle ◽  
M. D. Bremser ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Angular Correlation ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Heavy Ion ◽  
Correlation Spectroscopy ◽  
Lattice Location ◽  
Structural Defects ◽  
Implantation Damage ◽  
Emission Channeling

ABSTRACTSingle crystalline GaN-layers were implanted with radioactive 111In ions. The lattice location of the ions and the recovery of the implantation induced damage was studied using the emission channeling technique and perturbed-γγ-angular-correlation spectroscopy as a function of the annealing temperature. We find the majority of indium atoms on substitutional sites even directly after room temperature implantation, but within a heavily disturbed surrounding. During isochronal annealing treatments in vacuum, a gradual recovery of the implantation damage takes place between 873 K and 1173 K. After 1173 K annealing about 50 % of the In atoms occupy substitutional lattice sites with defect free surroundings.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

Temperature Dependent Line-Shape of the Silicon Dangling Bond EPR-Resonance in Polycrystalline Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
N. H. Nickel ◽  
E. A. Schiff
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Polycrystalline Silicon ◽  
Room Temperature ◽  
Dangling Bond ◽  
Temperature Dependent ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Motional Narrowing ◽  
G Value ◽  
Electron Paramagnetic

AbstractThe temperature dependence of the silicon dangling-bond resonance in polycrystalline (poly-Si) and amorphous silicon (a-Si:H) was measured. At room temperature, electron paramagnetic resonance (EPR) measurements reveal an isotropie g-value of 2.0055 and a line width of 6.5 and 6.1 G for Si dangling-bonds in a-Si:H and poly-Si, respectively. In both materials spin density and g-value are independent of temperature. While in a-Si:H the width of the resonance did not change with temperature, poly-Si exhibits a remarkable T dependence of ΔHpp. In unpassivated poly-Si a pronounced decrease of ΔHpp is observed for temperatures above 300 K. At 384 K ΔHpp reaches a minimum of 5.1 G, then increases to 6.1 G at 460 K, and eventually decreases to 4.6 G at 530 K. In hydrogenated poly-Si ΔHpp decreases monotonically above 425 K. The decrease of ΔHpp is attributed to electron hopping causing motional narrowing. An average hopping distance of 15 and 17.5 Å was estimated for unhydrogenated and H passivated poly-Si, respectively.

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