Transportation of Na and Li in Hydrothermally Grown ZnO

2009 ◽  
Vol 1201 ◽  
Author(s):  
Pekka Tapio Neuvonen ◽  
Lasse Vines ◽  
Klaus Magnus Johansen ◽  
Anders Hallén ◽  
Bengt Gunnar Svensson ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Formation Energy ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Constant ◽  
Zinc Vacancy ◽  
Diffusion Source ◽  
Secondary Ion ◽  
Zinc Site ◽  
Limited Diffusion

AbstractSecondary ion mass spectrometry has been applied to study the transportation of Na and Li in hydrothermally grown ZnO. A dose of 1015 cm-2 of Na+ was implanted into ZnO to act as a diffusion source. A clear trap limited diffusion is observed at temperatures above 550 °C. From these profiles, an activation energy for the transport of Na of ∼1.7 eV has been extracted. The prefactor for the diffusion constant and the solid solubility of Na cannot be deduced independently from the present data but their product estimated to be ∼3 × 1016 cm-1s-1. A dissociation energy of ∼2.4 eV is extracted for the trapped Na. The measured Na and Li profiles show that Li and Na compete for the same traps and interact in a way that Li is depleted from Na-rich regions. This is attributed to a lower formation energy of Na-on-zinc-site than that for Li-on-zinc-site defects and the zinc vacancy is considered as a major trap for migrating Na and Li atoms. Consequently, the diffusivity of Li is difficult to extract accurately from the present data, but in its interstitial configuration Li is indeed highly mobile having a diffusivity in excess of 10-11 cm2s-1 at 500 °C.

Te Induced AlAs/GaAs Superlattice Mixing

1988 ◽  
Vol 126 ◽  
Author(s):  
P. Mel ◽  
S. A. Schwarz ◽  
T. Venkatesan ◽  
C. L. Schwartz ◽  
E. Colas
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Diffusion Coefficient ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Vapor ◽  
Temperature Range ◽  
The Relationship ◽  
Secondary Ion

ABSTRACTTe enhanced mixing of AlAs/GaAs superlattice has been observed by secondary ion mass spectrometry. The superlattice sample was grown by organometallic chemical vapor deposition and doped with Te at concentrations of 2×1017 to 5×1018 cm−.3 In the temperature range from 700 to 1000 C, a single activation energy for the Al diffusion of 2.9 eV was observed. Furthermore, it has been found that the relationship between the Al diffusion coefficient and Te concentration is linear. Comparisons have been made between Si and Te induced superlattice mixing.

Hydrogen Dynamics and Tee Distribution of H Sites in Undoped a-Si:H and a-Ge:H

1991 ◽  
Vol 219 ◽  
Author(s):  
R. Shinar ◽  
X.-L. Wu ◽  
S. Mitra ◽  
J. Shinar
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Long Range ◽  
Secondary Ion Mass Spectrometry ◽  
Ir Studies ◽  
Multiple Trapping ◽  
Ion Mass Spectrometry ◽  
Secondary Ion ◽  
Trapping Sites

ABSTRACTSecondary ion mass spectrometry and IR studies of long-range hydrogen motion in undoped a-Si:H and a-Ge:H of varying H content and microstructure are reviewed and discussed. In particular, their relation to the multiple trapping (MT) model, the role of microvoids, the significance of the Meyer-Neldel relation (MNR), and the nature of H sites is addressed. It is suggested that while the MT mechanism may be significant in a-Si:H of low H content Cfj, it is largely marginal in films where CH ≥ 10 at.% H and in a-Ge:H. Mono Si-H bonds on microvoid surfaces are apparently deep H trapping sites up to ∼ 400°C, but H is desorbed from such sites in a-Ge:H above 180°C. The MNR between the diffusional activation energy and prefactor is observed among the various a-Si:H and a-Ge:H, but its significance is questionable, and may be due to the MT mechanism only in low H content a-Si:H. The nature of the distribution of H sites is also discussed.

Study of Fe Diffusion in Cr2O3 by Secondary Ion Mass Spectrometry

2005 ◽  
Vol 237-240 ◽  
pp. 940-945
Author(s):  
Antônio Claret Soares Sabioni ◽  
Anne Marie Huntz ◽  
F. Silva ◽  
François Jomard
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Bulk Diffusion ◽  
Grain Boundary Diffusion ◽  
Iron Diffusion ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

Chromia protective layers are used to prevent corrosion by oxidation of many alloys, such as the stainless steels, for instance. To check if chromia is a barrier to the outward diffusion of iron in these alloys, iron diffusion in chromia was studied in both polycrystals and oxide films formed by oxidation of Ni-30Cr alloy in the temperature range 700-1100°C at an oxygen pressure equal to 10-4 atm. An iron film of about 70 nm thick was deposited on the chromia surface, and after the diffusing treatment, the iron depth profiles were established by secondary ion mass spectrometry (SIMS). Using a solution of the Fick’s second law for diffusion from a thick film, effective or bulk diffusion coefficients were determined in a first penetration domain. Then, Le Claire’s and Hart’s models allowed both the bulk diffusion coefficient and the grain boundary diffusion parameter (aDgbd) to be obtained in a second penetration domain. Iron bulk and grain boundary diffusion does not vary significantly according to the nature-microstructure of chromia. The activation energy of grain boundary diffusion is at least equal or even greater than the activation energy of bulk diffusion, probably on account of segregation phenomena. Iron diffusion was compared to cationic self-diffusion and related to the protective character of chromia.

Diffusion of Hydrogen in 6H Silicon Carbide

1996 ◽  
Vol 423 ◽  
Author(s):  
M. K. Linnarsson ◽  
J. P. Doyle ◽  
B. G. Svensson
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Silicon Carbide ◽  
Diffusion Coefficient ◽  
Secondary Ion Mass Spectrometry ◽  
Depth Profiling ◽  
Defect Complexes ◽  
Induced Defects ◽  
Secondary Ion ◽  
Diffusion Of Hydrogen

Abstract6H polytype silicon carbide (SiC) samples of n-type have been implanted with 50 keV H+ ions and subsequently annealed at temperatures between 200 °C and 1150 °C. Using depth profiling by secondary ion mass spectrometry motion of hydrogen is observed in the implanted region for temperatures above 700 °C. A diffusion coefficient of ∼10−14 cm2/s is extracted at 800°C with an approximate activation energy of ∼3.5 eV. Hydrogen displays strong interaction with the implantation-induced defects and stable hydrogen-defect complexes are formed. These complexes anneal out at temperatures in excess of 900°C and are tentatively identified as Carbon-Hydrogen centers at a Si vacancy.

Boron Diffusion in Bulk Cobalt Disilicide

1990 ◽  
Vol 187 ◽  
Author(s):  
P. Gas ◽  
C. Zaring ◽  
B.G. Svensson ◽  
M. Östling ◽  
H.J. Whitlow ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Thin Films ◽  
Activation Energy ◽  
Surface Layer ◽  
Secondary Ion Mass Spectrometry ◽  
Lattice Diffusion ◽  
Boron Diffusion ◽  
Cobalt Disilicide ◽  
Boron Distribution ◽  
Secondary Ion

AbstractThe lattice diffusion of boron in bulk cobalt disilicide has been studied at temperatures between 450 and 950°C. Two different diffusion sources, a deposited surface layer of boron and an implanted boron distribution, were used. The lattice diffusion coefficient has been deduced from the boron profiles measured by secondary ion mass spectrometry (SIMS); in the studied temperature range the coefficient varies between 6.2×10−17 and 3.0× 10−11 cm2/s with an activation energy of 2.0 eV. These values reveal a very rapid lattice diffusion and agree with results reported previously in the literature concerning redistribution of boron implanted in thin films of CoSi2, and it also emphasizes the important role played by interfaces during the boron redistribution.

Aluminum and boron diffusion in 4H-SiC

2002 ◽  
Vol 742 ◽  
Author(s):  
M. K. Linnarsson ◽  
M. S. Janson ◽  
A. Schöner ◽  
B. G. Svensson
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Strong Dependence ◽  
Solubility Limit ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Al Content ◽  
Diffusion Source ◽  
P Type ◽  
Secondary Ion

ABSTRACTA brief survey is given of some recent result of boron diffusion in low doped n-type (intrinsic) and p-type 4H-SiC. Aluminum diffusion and solubility limit in 4H-SiC are also discussed. Ion implantation of boron has been performed in epitaxial material to form a diffusion source but also epitaxial 4H-SiC structures, with heavily boron or aluminum doped layers prepared by vapor phase epitaxy have been studied. Heat treatments have been made at temperatures ranging from 1100 to 2050°C for 5 minutes up to 64 h. Secondary ion mass spectrometry has been utilized for analysis. For boron diffusion in acceptor doped 4H-SiC, 4×1019 Al atoms/cm3, an activation energy of 5.3 eV has been determined and a strong dependence on Al content for the diffusion coefficient is revealed. Transient enhanced diffusion of ion-implanted boron in intrinsic 4H-SiC samples is discussed. Solubility limits of ∼1×1020 Al/cm3 (1700°C) and <1×1020 B/cm3 (1900°C) have been deduced.

scholarly journals Hydrogen Migration in Single Crystalline ZnO

2007 ◽  
Vol 1035 ◽  
Author(s):  
Klaus Magnus Håland Johansen ◽  
Jens Sherman Christensen ◽  
Edouard V. Monakhov ◽  
Andrej Yu. Kuznetsov ◽  
Bengt Gunnar Svensson
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Zinc Oxide ◽  
Diffusion Model ◽  
Peak Concentration ◽  
Secondary Ion Mass Spectrometry ◽  
Single Crystalline ◽  
Hydrogen Migration ◽  
Secondary Ion ◽  
Diffusion Profiles

AbstractHydrogen has been proposed as one of the contributors to the native n-type doping in as-grown Zinc Oxide and can also be used as an active (intentional) n-type dopant. In this work we have employed Secondary Ion Mass Spectrometry (SIMS) to study deuterium diffusion profiles in single crystalline ZnO. The samples used are hydrothermally grown, high-resistive (10 kΩ cm) monocrystalline ZnO implanted with deuterium to a dose of 1×1015 cm−2 yielding a peak concentration of approximately 5 × 1018 cm−3 at a depth of 2.2 µm. Diffusion profiles have been studied after 30 minutes isochronal heat treatments from 100ºC up to 400ºC in steps of 50ºC. The observed redistribution can be explained by employing a diffusion model which includes trapping of 2H by Li-impurities and an activation energy of 0.85 eV is extracted for the diffusion of 2H.

How SIMS microscopy can be used in medicine

1992 ◽  
Vol 50 (2) ◽  
pp. 1602-1603
Author(s):  
Philippe Fragu
Keyword(s):  
Mass Spectrometry ◽  
Biomedical Applications ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Elements ◽  
Biological Applications ◽  
The Past ◽  
Potential Source ◽  
Secondary Ion ◽  
Chemical Integrity ◽  
Scientific Endeavour

The identification, localization and quantification of intracellular chemical elements is an area of scientific endeavour which has not ceased to develop over the past 30 years. Secondary Ion Mass Spectrometry (SIMS) microscopy is widely used for elemental localization problems in geochemistry, metallurgy and electronics. Although the first commercial instruments were available in 1968, biological applications have been gradual as investigators have systematically examined the potential source of artefacts inherent in the method and sought to develop strategies for the analysis of soft biological material with a lateral resolution equivalent to that of the light microscope. In 1992, the prospects offered by this technique are even more encouraging as prototypes of new ion probes appear capable of achieving the ultimate goal, namely the quantitative analysis of micron and submicron regions. The purpose of this review is to underline the requirements for biomedical applications of SIMS microscopy.Sample preparation methodology should preserve both the structural and the chemical integrity of the tissue.

Imaging of Al-Li-Cu alloys with a Scanning Ion Microprobe

1990 ◽  
Vol 48 (2) ◽  
pp. 314-315
Author(s):  
K.K. Soni ◽  
D.B. Williams ◽  
J.M. Chabala ◽  
R. Levi-Setti ◽  
D.E. Newbury
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Equilibrium Phase ◽  
Icosahedral Symmetry ◽  
Ion Microprobe ◽  
X Ray ◽  
Cu Alloys ◽  
Two Phases ◽  
The University ◽  
Secondary Ion

In contrast to the inability of x-ray microanalysis to detect Li, secondary ion mass spectrometry (SIMS) generates a very strong Li+ signal. The latter’s potential was recently exploited by Williams et al. in the study of binary Al-Li alloys. The present study of Al-Li-Cu was done using the high resolution scanning ion microprobe (SIM) at the University of Chicago (UC). The UC SIM employs a 40 keV, ∼70 nm diameter Ga+ probe extracted from a liquid Ga source, which is scanned over areas smaller than 160×160 μm2 using a 512×512 raster. During this experiment, the sample was held at 2 × 10-8 torr.In the Al-Li-Cu system, two phases of major importance are T1 and T2, with nominal compositions of Al2LiCu and Al6Li3Cu respectively. In commercial alloys, T1 develops a plate-like structure with a thickness <∼2 nm and is therefore inaccessible to conventional microanalytical techniques. T2 is the equilibrium phase with apparent icosahedral symmetry and its presence is undesirable in industrial alloys.

Sign in / Sign up

Export Citation Format

Share Document