A Sims Study of Electroluminescent Phosphors: SrS:Cu

1999 ◽  
Vol 558 ◽  
Author(s):  
Lily H. Zhang ◽  
Larry Wang ◽  
Wusheng Tong ◽  
YongBao Xin
Keyword(s):  
Material Characterization ◽  
Secondary Ion Mass Spectrometry ◽  
Dopant Concentration ◽  
Thermal Quenching ◽  
Areal Density ◽  
Device Performance ◽  
Cell Temperature ◽  
Co Doping ◽  
Doping Effects ◽  
Secondary Ion

ABSTRACTThis study has used secondary ion mass spectrometry (SIMS) as a technique for thin film EL material characterization. It has shown that the Cu dopant concentration in the SrS films directly correlates with the luminescent brightness of the EL devices. A series of SrS:Cu, Y were grown using MBE to study the Y co-doping effects. It has been found that Y peak concentration and areal density in the SrS increased as the Y evaporation cell temperature was increased. The maximum PL intensity was found in the sample grown in the middle of the Y cell temperature range used. The Y co-doping has shown to reduce the thermal quenching effects in SrS EL devices. Therefore, in this series of samples, a good correlation has been found between Y and Cu concentration and the EL device performance characteristics.

A Sims Study of Electroluminescent Phosphors: SrS:Cu

1999 ◽  
Vol 560 ◽  
Author(s):  
Lily H. Zhang ◽  
Larry Wang ◽  
Wusheng Tong ◽  
YongBao Xin
Keyword(s):  
Material Characterization ◽  
Secondary Ion Mass Spectrometry ◽  
Dopant Concentration ◽  
Thermal Quenching ◽  
Areal Density ◽  
Device Performance ◽  
Cell Temperature ◽  
Co Doping ◽  
Doping Effects ◽  
Secondary Ion

ABSTRACTThis study has used secondary ion mass spectrometry (SIMS) as a technique for thin film EL material characterization. It has shown that the Cu dopant concentration in the SrS films directly correlates with the luminescent brightness of the EL devices. A series of SrS:Cu,Y were grown using MBE to study the Y co-doping effects. It has been found that Y peak concentration and areal density in the SrS increased as the Y evaporation cell temperature was increased. The maximum PL intensity was found in the sample grown in the middle of the Y cell temperature range used. The Y co-doping has shown to reduce the thermal quenching effects in SrS EL devices. Therefore, in this series of samples, a good correlation has been found between Y and Cu concentration and the EL device performance characteristics.

Co-doping Approach for β-type ZnO with Combinatorial Laser MBE Method

2001 ◽  
Vol 700 ◽  
Author(s):  
A. Tsukazaki ◽  
H. Saito ◽  
M. Sumiya ◽  
K. Tamura ◽  
S. Fuke ◽  
...  
Keyword(s):  
Dopant Concentration ◽  
Zno Films ◽  
Precise Control ◽  
Co Doping ◽  
N Concentration ◽  
Different Temperatures ◽  
Laser Mbe ◽  
Systematic Control ◽  
Secondary Ion ◽  
Pure Single Crystal

AbstractWe show here three different ways of combinatorial experiments for achieving precise control of dopant concentration in ZnO thin films. Alternating ablation of highly pure single crystal target and ceramics target doped with concentrated Ga dopant yielded in a systematic control of Ga concentration with keeping minimal contamination of undesired impurity. Secondary ion mass spectroscopy for a stack of several ZnO films grown at different temperatures under a constant exposure of N radical gave us a systematic calibration curve for the N concentration. With using a special heating method to give a controlled temperature gradient on a substrate, we demonstrate that continuous spread of N concentration can be built in a film on a substrate with keeping constant Ga concentration. Such systematic experiments taking into account the “combinatorial” concept enable us to make ZnO films with controlled dopant concentrations.

The Effect of Temperature and Si Concentration on the Mixing of AlAs/GaAs Superlattices

1986 ◽  
Vol 77 ◽  
Author(s):  
Ping Mei ◽  
H. W. Yoon ◽  
T. Venkatesan ◽  
S. A. Schwarz ◽  
J. P. Harbison
Keyword(s):  
Activation Energy ◽  
Molecular Beam ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Length ◽  
Dopant Concentration ◽  
Effect Of Temperature ◽  
Surface Layers ◽  
Near Surface ◽  
Depth Profiles ◽  
Secondary Ion

ABSTRACTThe intermixing of AlAs/GaAs superlattices has been investigated as a function of Si concentration following anneals in the range of 500 to 900 C. The superlattice samples were grown by molecular beam epitaxy(MBE) and the near surface layers were doped with silicon at concentrations of 2×10 to 5×1018 cm-3. Si and Al depth profiles were measured with secondary ion mass spectrometry (SIMS).The diffusion length and activation energy of Al as a function of silicon dopant concentration are derived from the SIMS data. In the temperature range studied an activation energy for the Al interdiffusion of -4eV is observed with the diffusion coefficients increasing rapidly with Si concentration.

Cobalt Doping as the Controlling Factor of Oxygen Diffusivity in ZnO by More than Four Orders of Magnitude

2015 ◽  
Vol 363 ◽  
pp. 85-90 ◽  
Author(s):  
Minako Hashiguchi ◽  
Isao Sakaguchi ◽  
Reona Miyazaki ◽  
Kazunori Takada ◽  
Naoki Ohashi
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Cobalt Doping ◽  
Co Doping ◽  
Isotope Tracer ◽  
Oxygen Diffusivity ◽  
Co Concentration ◽  
Bulk Oxygen ◽  
Doped Zno ◽  
Secondary Ion ◽  
Zno Ceramics

Oxygen diffusivity in ZnO ceramics doped with cobalt was investigated using an isotope tracer method. The oxygen isotope (18O) was introduced by 18O/16O exchange annealing in an 18O2 atmosphere, and the depth profile of the 18O concentration was analyzed by secondary ion mass spectrometry. The results show that oxygen diffusivity in ZnO steeply increases with increasing Co concentration. In fact, the bulk oxygen diffusivity in 15 mol% Co-doped ZnO was four orders of magnitude greater than that of nominally non-doped ZnO. Oxygen diffusivity at grain boundaries was also enhanced by Co-doping.

scholarly journals Dopant Incorporation Efficiency in CVD Silicon Carbide Epilayers

1995 ◽  
Vol 410 ◽  
Author(s):  
D. J. Larkin
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Semiconductor Device ◽  
Dopant Concentration ◽  
Competition Effect ◽  
Dopant Incorporation ◽  
The Many ◽  
Site Competition ◽  
Secondary Ion ◽  
Dopant Source ◽  
Incorporation Efficiency

ABSTRACTIn order to ensure reproducible and reliable SiC semiconductor device characteristics, controlled dopant incorporation must be accomplished. Some of the many factors which greatly influence dopant incorporation are the site-competition effect, SiC(0001) substrate polarity, substrate temperature, and the dopant-source reactor concentration. In this paper, dopant incorporation is considered and compared for various dopants in the context of dopant incorporation efficiency. By using secondary ion mass spectrometry (SIMS), the relative dopant incorporation efficiencies were calculated by dividing the SIMS determined dopant concentration in the resulting epitaxial layer by the intentional gas phase dopant concentration used during the SiC CVD. Specifically, the relative magnitudes of dopant incorporation efficiencies for nitrogen, phosphorus, and boron in 6H-SiC (0001) Si-face epitaxial layers are compared as a function of the site-competition effect and the dopant-source reactor concentrations. This serves as a first approximation for comparison of the relative “doping potencies” of some common dopants used in SiC CVD epitaxial growth.

Characterization of Atmospheric Impurities in Tungsten Silicide Films by Secondary Ion Mass Spectrometry (SIMS)

1995 ◽  
Vol 402 ◽  
Author(s):  
Salman Mitha ◽  
David B. Sams
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Relative Sensitivity ◽  
Areal Density ◽  
Primary Beam ◽  
Tungsten Silicide ◽  
Secondary Ions ◽  
Signal Change ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

AbstractConcentrations of atmospheric impurities in tungsten silicide films and impurity areal densities silicide / polysilicon interface can usually only be measured using Secondary Ion Mass Spectrometry (SIMS). Normally these measurements are made using a Cs+ primary beam with negative secondary ions being monitored. This mode is used to achieve the best possible detection limits. However the Relative Sensitivity Factors (RSFs) used to quantify the impurities, as well as the reference matrix signal, change dramatically in going from one matrix to the other. These changes affect the quantification of the impurities at the interface. An alternate mode of analysis would be to use the Cs+ primary beam and monitor MCs+ ions, where M is the impurity, because these ions typically have less matrix dependent RSFs. We measure carbon and oxygen in a tungsten silicide film on polysilicon using both modes of analysis. Preliminary data indicates that we have determined the absolute accuracy of interface areal density to within a factor of 2.2 for oxygen and to within a factor of 1.5 for carbon.

Growth and Characterization of Piezoelectrically Enhanced Acceptor-Type AlGaN/GaN Heterostructures

1999 ◽  
Vol 595 ◽  
Author(s):  
A. Michel ◽  
D. Hanser ◽  
R.F. Davis ◽  
D. Qiao ◽  
S.S. Lau ◽  
...  
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Standard Sample ◽  
Acceptor Doping ◽  
Modulation Doping ◽  
Doping Effects ◽  
Sheet Conductance ◽  
Gan Heterostructure ◽  
Secondary Ion ◽  
Mg Doped

AbstractAcceptor (Mg)-doped AlGaN/GaN heterostructures were grown via MOVPE and compared to similarly doped GaN standard films grown in the same reactor. Chemical analysis of the films, via secondary ion mass spectrometry (SIMS), revealed comparable Mg concentrations of ∼2×1019 atoms/cm3 in all films. The Mg-doped GaN standard sample had a sheet conductance of 7-μS compared to a sheet conductance of 20-μS for an AlGaN/GaN heterostructure. The sheet conductance of the AlGaN/GaN heterostructures was higher due to piezoelectric acceptor doping and modulation doping effects in addition to conventional Mg acceptor doping.

scholarly journals Growth and Characterization of Piezoelectrically Enhanced Acceptor-Type AlGaN/GaN Heterostructures

2000 ◽  
Vol 5 (S1) ◽  
pp. 605-611
Author(s):  
A. Michel ◽  
D. Hanser ◽  
R.F. Davis ◽  
D. Qiao ◽  
S.S. Lau ◽  
...  
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Standard Sample ◽  
Acceptor Doping ◽  
Modulation Doping ◽  
Doping Effects ◽  
Sheet Conductance ◽  
Gan Heterostructure ◽  
Secondary Ion ◽  
Mg Doped

Acceptor (Mg)-doped AlGaN/GaN heterostructures were grown via MOVPE and compared to similarly doped GaN standard films grown in the same reactor. Chemical analysis of the films, via secondary ion mass spectrometry (SIMS), revealed comparable Mg concentrations of ∼2×1019 atoms/cm3 in all films. The Mg-doped GaN standard sample had a sheet conductance of 7-μS compared to a sheet conductance of 20-μS for an AlGaN/GaN heterostructure. The sheet conductance of the AlGaN/GaN heterostructures was higher due to piezoelectric acceptor doping and modulation doping effects in addition to conventional Mg acceptor doping.

Aspects of high-resolution imaging with a scanning ion microprobe

1986 ◽  
Vol 44 ◽  
pp. 750-751
Author(s):  
R. Levi-Setti ◽  
J. M. Chabala ◽  
Y. L. Wang
Keyword(s):  
Metal Ion ◽  
Secondary Ion Mass Spectrometry ◽  
Chromatic Aberration ◽  
Ion Source ◽  
Ion Microprobe ◽  
Emission Pattern ◽  
Intrinsic Resolution ◽  
Resolution Imaging ◽  
20 Nm ◽  
Secondary Ion

We have shown the feasibility of 20 nm lateral resolution in both topographic and elemental imaging using probes of this size from a liquid metal ion source (LMIS) scanning ion microprobe (SIM). This performance, which approaches the intrinsic resolution limits of secondary ion mass spectrometry (SIMS), was attained by limiting the size of the beam defining aperture (5μm) to subtend a semiangle at the source of 0.16 mr. The ensuing probe current, in our chromatic-aberration limited optical system, was 1.6 pA with Ga+ or In+ sources. Although unique applications of such low current probes have been demonstrated,) the stringent alignment requirements which they imposed made their routine use impractical. For instance, the occasional tendency of the LMIS to shift its emission pattern caused severe misalignment problems.

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.

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