Atom probe reveals the structure of Inx Ga1–xN based quantum wells in three dimensions

2008 ◽  
Vol 245 (5) ◽  
pp. 861-867 ◽  
Author(s):  
M. J. Galtrey ◽  
R. A. Oliver ◽  
M. J. Kappers ◽  
C. McAleese ◽  
D. Zhu ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Atom Probe ◽  
Three Dimensions

Position-Sensitive Atom Probe and Stem Analysis of the Microchemistry of GaInAs/Inp Quantum Wells

1989 ◽  
Vol 148 ◽  
Author(s):  
J. Alex Liddle ◽  
N.J. Long ◽  
A.G. Norman ◽  
A. Cerezo ◽  
C.R.M. Grovenor
Keyword(s):  
Quantum Wells ◽  
Atom Probe ◽  
Three Dimensions ◽  
Chemical Information ◽  
Stem Analysis ◽  
Analysis Techniques ◽  
Phosphorous Content ◽  
Position Sensitive ◽  
Complementary Analysis ◽  
Better Than

ABSTRACTThe recently developed techniques of pulsed laser atom probe microanalysis (PLAP) and position sensitive atom probe (POSAP) have been applied to the study of quantum well interfaces in samples that have also been well characterised by the more conventional techniques of TEM and STEM. These techniques have the potential for providing chemical information with a spatial resolution of better than 2nm, but the atom probe has the ability to independently resolve morphological and microchemical features of interfaces in three dimensions.This paper presents results taken from GaInAs/lnP MOCVD-grown samples, comparing information on well composition, and on the chemical abruptness and morphological roughness of interfaces using complementary analysis techniques. We have concentrated on obtaining reliable quantitative data on the phosphorous content of the GaInAs wells and on the gallium and arsenic contents of the InP barrier layers.

Characterisation of multilayer materials using a position-sensitive atom probe

1990 ◽  
Vol 48 (4) ◽  
pp. 624-625
Author(s):  
RAD Mackenzie ◽  
G D W Smith ◽  
A. Cerezo ◽  
J A Liddle ◽  
CRM Grovenor ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Spatial Information ◽  
Chemical Vapour ◽  
Atom Probe ◽  
Organic Chemical ◽  
Growth Stages ◽  
Multiple Quantum ◽  
Quartz Wool ◽  
Position Sensitive

The position sensitive atom probe (POSAP), described briefly elsewhere in these proceedings, permits both chemical and spatial information in three dimensions to be recorded from a small volume of material. This technique is particularly applicable to situations where there are fine scale variations in composition present in the material under investigation. We report the application of the POSAP to the characterisation of semiconductor multiple quantum wells and metallic multilayers.The application of devices prepared from quantum well materials depends on the ability to accurately control both the quantum well composition and the quality of the interfaces between the well and barrier layers. A series of metal organic chemical vapour deposition (MOCVD) grown GaInAs-InP quantum wells were examined after being prepared under three different growth conditions. These samples were observed using the POSAP in order to study both the composition of the wells and the interface morphology. The first set of wells examined were prepared in a conventional reactor to which a quartz wool baffle had been added to promote gas intermixing. The effect of this was to hold a volume of gas within the chamber between growth stages, leading to a structure where the wells had a composition of GalnAsP lattice matched to the InP barriers, and where the interfaces were very indistinct. A POSAP image showing a well in this sample is shown in figure 1. The second set of wells were grown in the same reactor but with the quartz wool baffle removed. This set of wells were much better defined, as can be seen in figure 2, and the wells were much closer to the intended composition, but still with measurable levels of phosphorus. The final set of wells examined were prepared in a reactor where the design had the effect of minimizing the recirculating volume of gas. In this case there was again further improvement in the well quality. It also appears that the left hand side of the well in figure 2 is more abrupt than the right hand side, indicating that the switchover at this interface from barrier to well growth is more abrupt than the switchover at the other interface.

Challenges Associated with the Characterisation of Nanocrystalline Materials Using Atom Probe Tomography

2010 ◽  
Vol 654-656 ◽  
pp. 2366-2369 ◽  
Author(s):  
Feng Zai Tang ◽  
Talukder Alam ◽  
Michael P. Moody ◽  
Baptiste Gault ◽  
Julie M. Cairney
Keyword(s):  
Quantitative Analysis ◽  
Atom Probe Tomography ◽  
Nanocrystalline Materials ◽  
Atom Probe ◽  
Atomic Scale ◽  
Three Dimensions ◽  
Specimen Preparation ◽  
Compositional Information

Atom probe tomography provides compositional information in three dimensions at the atomic scale, and is therefore extremely suited to the study of nanocrystalline materials. In this paper we present atom probe results from the investigation of nanocomposite TiSi¬Nx coatings and nanocrystalline Al. We address some of the major challenges associated with the study of nanocrystalline materials, including specimen preparation, visualisation, common artefacts in the data and approaches to quantitative analysis. We also discuss the potential for the technique to relate crystallographic information to the compositional maps.

scholarly journals Analysis of Radiation Damage in Light Water Reactors: Comparison of Cluster Analysis Methods for the Analysis of Atom Probe Data

2017 ◽  
Vol 23 (2) ◽  
pp. 366-375 ◽  
Author(s):  
Jonathan M. Hyde ◽  
Gérald DaCosta ◽  
Constantinos Hatzoglou ◽  
Hannah Weekes ◽  
Bertrand Radiguet ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Radiation Damage ◽  
Defect Formation ◽  
Chemical Species ◽  
Atom Probe ◽  
Three Dimensions ◽  
Multiple Sources ◽  
Damage Models ◽  
Combining Data ◽  
Water Reactors

AbstractIrradiation of reactor pressure vessel (RPV) steels causes the formation of nanoscale microstructural features (termed radiation damage), which affect the mechanical properties of the vessel. A key tool for characterizing these nanoscale features is atom probe tomography (APT), due to its high spatial resolution and the ability to identify different chemical species in three dimensions. Microstructural observations using APT can underpin development of a mechanistic understanding of defect formation. However, with atom probe analyses there are currently multiple methods for analyzing the data. This can result in inconsistencies between results obtained from different researchers and unnecessary scatter when combining data from multiple sources. This makes interpretation of results more complex and calibration of radiation damage models challenging. In this work simulations of a range of different microstructures are used to directly compare different cluster analysis algorithms and identify their strengths and weaknesses.

Ultrafast Carrier Dynamics, Optical Amplification, and Lasing in Nanocrystal Quantum Dots

MRS Bulletin ◽  
2001 ◽  
Vol 26 (12) ◽  
pp. 998-1004 ◽  
Author(s):  
Victor I. Klimov ◽  
Moungi G. Bawendi
Keyword(s):  
Quantum Dots ◽  
Quantum Wells ◽  
Quantum Wires ◽  
Electronic States ◽  
Three Dimensions ◽  
Band Edge ◽  
Lasing Threshold ◽  
Wide Energy Range ◽  
Band Edge Emission ◽  
Edge States

Semiconductor materials are widely used in both optically and electrically pumped lasers. The use of semiconductor quantum wells (QWs) as optical-gain media has resulted in important advances in laser technology. QWs have a two-dimensional, step-like density of electronic states that is nonzero at the band edge, enabling a higher concentration of carriers to contribute to the band-edge emission and leading to a reduced lasing threshold, improved temperature stability, and a narrower emission line. A further enhancement in the density of the band-edge states and an associated reduction in the lasing threshold are in principle possible using quantum wires and quantum dots (QDs), in which the confinement is in two and three dimensions, respectively. In very small dots, the spacing of the electronic states is much greater than the available thermal energy (strong confinement), inhibiting thermal depopulation of the lowest electronic states. This effect should result in a lasing threshold that is temperatureinsensitive at an excitation level of only 1 electron-hole (e-h) pair per dot on average. Additionally, QDs in the strongconfinement regime have an emission wavelength that is a pronounced function of size, adding the advantage of continuous spectral tunability over a wide energy range simply by changing the size of the dots.

scholarly journals Indium clustering in a-plane InGaN quantum wells as evidenced by atom probe tomography

2015 ◽  
Vol 106 (7) ◽  
pp. 072104 ◽  
Author(s):  
Fengzai Tang ◽  
Tongtong Zhu ◽  
Fabrice Oehler ◽  
Wai Yuen Fu ◽  
James T. Griffiths ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
Ingan Quantum Wells

True Atomic-Scale Imaging in Three Dimensions: A Review of the Rebirth of Field-Ion Microscopy

2017 ◽  
Vol 23 (2) ◽  
pp. 210-220 ◽  
Author(s):  
Francois Vurpillot ◽  
Frédéric Danoix ◽  
Matthieu Gilbert ◽  
Sebastian Koelling ◽  
Michal Dagan ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Atom Probe ◽  
Image Sequences ◽  
Atomic Scale ◽  
Three Dimensions ◽  
Physical Metallurgy ◽  
Science And Engineering ◽  
Computing Power ◽  
Field Ion Microscopy ◽  
Ion Microscopy

AbstractThis article reviews recent advances utilizing field-ion microscopy (FIM) to extract atomic-scale three-dimensional images of materials. This capability is not new, as the first atomic-scale reconstructions of features utilizing FIM were demonstrated decades ago. The rise of atom probe tomography, and the application of this latter technique in place of FIM has unfortunately severely limited further FIM development. Currently, the ubiquitous availability of extensive computing power makes it possible to treat and reconstruct FIM data digitally and this development allows the image sequences obtained utilizing FIM to be extremely valuable for many material science and engineering applications. This article demonstrates different applications of these capabilities, focusing on its use in physical metallurgy and semiconductor science and technology.

Ultra-high resolution chemical analysis by field-ion atom probe/position sensitive atom probe techniques

1991 ◽  
Vol 49 ◽  
pp. 486-487
Author(s):  
C.R.M. Grovenor ◽  
A. Cerezo ◽  
J.A. Liddle ◽  
R.A.D. Mackenzie ◽  
M.G. Hetherington ◽  
...  
Keyword(s):  
High Resolution ◽  
Sample Surface ◽  
Atom Probe ◽  
Three Dimensions ◽  
Very High Spatial Resolution ◽  
Chemical Profiles ◽  
Position Sensitive ◽  
Field Ion Microscope ◽  
Very High

The use of field ion microscopy based techniques in the study of the structure and chemistry of metallic and semiconducting materials with very high resolution is now well documented. The particular features of these techniques which result in the achievement of very high spatial resolution in images and chemical profiles are; the intrinsic magnification in a conventional field ion microscope of at least 106, the plane-by-plane desorption characteristic of field evaporation processes, and the excellent chemical specificity in a modern atom probe. In addition, we have developed in Oxford a new detector system for field ion based equipment in which both the chemical identity of evaporated ions and the position on the sample surface from which they were evaporated can be established. This allows the reconstruction of the evaporated volume in three dimensions, and this technique has been christened the Position Sensitive Atom Probe, POSAP. This abstract presents the results of two typical experiments illustrating the very high quality of the chemical data that can be obtained in both conventional atom probe and POSAP facilities.

Characterization of Nanoporous Materials with Atom Probe Tomography

2015 ◽  
Vol 21 (3) ◽  
pp. 557-563 ◽  
Author(s):  
Björn Pfeiffer ◽  
Torben Erichsen ◽  
Eike Epler ◽  
Cynthia A. Volkert ◽  
Piet Trompenaars ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Atom Probe ◽  
Nanoporous Materials ◽  
Three Dimensions ◽  
Chemical Information ◽  
Nanoporous Material ◽  
Open Cell ◽  
Dicobalt Octacarbonyl

AbstractA method to characterize open-cell nanoporous materials with atom probe tomography (APT) has been developed. For this, open-cell nanoporous gold with pore diameters of around 50 nm was used as a model system, and filled by electron beam-induced deposition (EBID) to obtain a compact material. Two different EBID precursors were successfully tested—dicobalt octacarbonyl [Co2(CO)8] and diiron nonacarbonyl [Fe2(CO)9]. Penetration and filling depth are sufficient for focused ion beam-based APT sample preparation. With this approach, stable APT analysis of the nanoporous material can be performed. Reconstruction reveals the composition of the deposited precursor and the nanoporous material, as well as chemical information of the interfaces between them. Thus, it is shown that, using an appropriate EBID process, local chemical information in three dimensions with sub-nanometer resolution can be obtained from nanoporous materials using APT.

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