Julie M. Cairney

Bio: Julie M. Cairney is an academic researcher from University of Sydney. The author has contributed to research in topics: Atom probe & Focused ion beam. The author has an hindex of 44, co-authored 247 publications receiving 7155 citations. Previous affiliations of Julie M. Cairney include University of Queensland & University of Erlangen-Nuremberg.

Atom Probe Microscopy

Abstract: Preface Acknowledgements List of Acronyms and Abbreviations List of Terms List of Non-SI Units and Constant Values PART I Fundamentals 1. Introduction 2. Field Ion Microscopy 2.1 Principles 2.1.1 Theory of field ionisation 2.1.2 'Seeing' atoms - field ion microscopy 2.1.3 Spatial resolution of the FIM 2.2 Instrumentation and Techniques for FIM 2.2.1 FIM instrumentation 2.2.2 eFIM or digital FIM 2.2.3 Tomographic FIM Techniques 2.3 Interpretation of FIM Images 2.3.1 Interpretation of the image in a pure material 2.3.2 Interpretation of the image for alloys 2.3.3 Selected applications of the FIM 2.3.4 Summary 3 From Field Desorption Microscopy to Atom Probe Tomography 3.1 Principles 3.1.1 Theory of field evaporation 3.1.2 'Analysing' atoms one-by-one: atom probe tomography 3.2 Instrumentation and Techniques for APT 3.2.1 Experimental setup 3.2.2 Field desorption microscopy 3.2.3 High voltage pulsing techniques 3.2.4 Laser pulsing techniques 3.2.5 Energy compensation techniques Part II Practical aspects 4. Specimen Preparation 4.1 Introduction 4.1.1 Sampling issues in microscopy for materials science and engineering 4.1.2 Specimen requirements 4.2 Polishing methods 4.2.1 The electropolishing process 4.2.2 Chemical polishing 4.2.3 Safety Considerations 4.2.4 Advantages and limitations 4.3 Broad ion beam techniques 4.4 Focused ion beam techniques 4.4.1 Cut-away methods 4.4.2 Lift-out methods 4.4.3 The final stages of FIB preparation 4.4.4 Understanding and minimising ion beam damage and other artefacts 4.5 Deposition methods 4.6 Methods for organic materials 4.6.1 Polymer microtips 4.6.2 Self-assembled monolayers 4.6.3 Cryopreparation 4.7 Other Methods 4.7.1 Dipping 4.7.2 Direct growth of suitable structures 4.8 Specimen geometry issues 4.8.1 Influence of specimen geometry on atom probe data 4.8.2 Stress states and specimen rupture 4.9 A guide to selecting an appropriate specimen preparation method 5. Experimental protocols in Field Ion Microscopy 5.1 Step-by-step procedures for FIM 5.2 Operational space of the field ion microscope 5.2.1 Imaging gas 5.2.2 Temperature 5.2.3 The best image field 5.2.4 Other parameters 5.2.5 Summary 6. Experimental protocols 6.1 Specimen alignment 6.2 Aspects of mass spectrometry 6.2.1 Detection of the ions 6.2.2 Mass spectra 6.2.3 Formation of the mass spectrum 6.2.4 Mass resolution 6.2.5 Common artefacts 6.2.6 Elemental identification 6.2.7 Measurement of the composition 6.2.8 Detectability 6.3 Operational space 6.3.1 Flight path 6.3.2 Temperature / Pulse fraction 6.3.3 Selecting the pulsing mode 6.3.4 Pulse rate 6.3.5 Detection rate 6.4 Specimen failure 6.5 Data quality assessment 6.5.1 Field desorption map 6.5.2 Mass spectrum 6.5.3 Multiple events 6.5.4 Discussion 7. Tomographic reconstruction 7.1 Projection of the ions 7.1.1 Estimation of the electric field 7.1.2 Field distribution 7.1.3 Ion trajectories 7.1.4 Point projection 7.1.5 Radial projection with angular compression 7.1.6 Discussion 7.2 Reconstruction 7.2.1 General considerations 7.2.2 Bas et al. protocol 7.2.3 Geiser et al. protocol 7.2.4 Gault et al. protocol 7.2.5 Reflectron-fitted instruments 7.2.6 Summary and discussion 7.3 Calibration of the parameters 7.3.2 Discussion 7.3.3 Limitations of the current procedure 7.4 Common artefacts 7.4.2 Correction of the reconstruction 7.5 Perspectives on the reconstruction in atom probe tomography 7.5.1 Advancing the reconstruction by correlative microscopy 7.5.2 In correlation with simulations 7.5.3 Alternative ways to exploit existing data 7.6 Spatial resolution in APT 7.6.1 Introduction 7.6.2 Means of investigation 7.6.3 Definition 7.6.4 On the in-depth resolution 7.6.5 On the lateral resolution 7.6.6 Optimisation of the spatial resolution 7.7 Lattice rectification PART III Applying atom probe techniques for materials science 8. Analysis techniques for atom probe tomography 8.1 Characterising the Mass Spectrum 8.1.1 Noise Reduction 8.1.2 Quantifying Peak Contributions via Isotope Natural Abundances 8.1.3 Spatially dependent identification of mass peaks 8.1.4 Multiple Detector Event Analyses 8.2 Characterising the chemical distribution 8.2.1 Quality of atom probe data 8.2.2 Random comparators 8.3 Grid-based counting statistics 8.3.1 Voxelisation 8.3.2 Density 8.3.3 Concentration analyses 8.3.4 Smoothing by delocalisation 8.3.5 Visualisation techniques based on iso-concentration and iso-density 8.3.6 One-dimensional profiles 8.3.7 Grid-based frequency distribution analyses 8.4 Techniques for describing atomic architecture 8.4.1 Nearest neighbour distributions 8.4.2 Cluster Identification Algorithms 8.4.3 Detection Efficiency Influence on Nanostructural Analyses 8.5 Radial Distribution 8.5.1 Radial distribution and pair correlation functions 8.5.2 Solute Short Range Order Parameters 8.6 Structural Analyses 8.6.1 Fourier Transforms for APT 8.6.2 Spatial Distribution Maps 8.6.3 Hough Transform 9. Atom probe microscopy and materials science 9.1 Compositional analysis 9.2 Defects/ dislocations 9.3 Solid solutions / clustering 9.4 Precipitates 9.5 Ordering reaction 9.6 Spinodal decomposition 9.7 Interface/boundaries/layers 9.8 Amorphous materials 9.9 Atom probe crystallography Appendices A. Appendix - chi2 distribution B. Appendix - Polishing chemicals and conditions C. File formats used in APT POS EPOS RNG RRNG ATO ENV PoSAP Cameca root files - RRAW, RHIT, ROOT D. Appendix - Image Hump Model Predictions E. Appendix - Essential Crystallography for APT Bravais lattices Notation Structure factor (F) rules for BCC, FCC, HCP Interplanar spacings (dhkl) Interplanar angles (phi) F. Stereographic Projections and commonly observed desorption maps Stereographic projection for the most commonly found structures and orientations Face-centred cubic Body-centred cubic Diamond cubic Hexagonal close-packed G. Periodic tables H. Kingham Curves I. List of elements and associated mass to charge ratios J. Possible element identity of peaks as a function of their location in the mass spectrum

Cu 2 ZnSnS 4 solar cells with over 10% power conversion efficiency enabled by heterojunction heat treatment

Abstract: Sulfide kesterite Cu2ZnSnS4 provides an attractive low-cost, environmentally benign and stable photovoltaic material, yet the record power conversion efficiency for such solar cells has been stagnant at around 9% for years. Severe non-radiative recombination within the heterojunction region is a major cause limiting voltage output and overall performance. Here we report a certified 11% efficiency Cu2ZnSnS4 solar cell with a high 730 mV open-circuit voltage using heat treatment to reduce heterojunction recombination. This heat treatment facilitates elemental inter-diffusion, directly inducing Cd atoms to occupy Zn or Cu lattice sites, and promotes Na accumulation accompanied by local Cu deficiency within the heterojunction region. Consequently, new phases are formed near the hetero-interface and more favourable conduction band alignment is obtained, contributing to reduced non-radiative recombination. Using this approach, we also demonstrate a certified centimetre-scale (1.11 cm2) 10% efficiency Cu2ZnSnS4 photovoltaic device; the first kesterite cell (including selenium-containing) of standard centimetre-size to exceed 10%. The emerging kesterite Cu2ZnSnS4 solar cell offers a potential low-cost, non-toxic, materially abundant platform for next-generation photovoltaics, yet its efficiency has been mired below 10%. Yan et al. now use post-heat treatment of the heterojunction to show device efficiencies that surpass 10%.

Observation of hydrogen trapping at dislocations, grain boundaries, and precipitates

Abstract: Hydrogen embrittlement of high-strength steel is an obstacle for using these steels in sustainable energy production. Hydrogen embrittlement involves hydrogen-defect interactions at multiple-length scales. However, the challenge of measuring the precise location of hydrogen atoms limits our understanding. Thermal desorption spectroscopy can identify hydrogen retention or trapping, but data cannot be easily linked to the relative contributions of different microstructural features. We used cryo-transfer atom probe tomography to observe hydrogen at specific microstructural features in steels. Direct observation of hydrogen at carbon-rich dislocations and grain boundaries provides validation for embrittlement models. Hydrogen observed at an incoherent interface between niobium carbides and the surrounding steel provides direct evidence that these incoherent boundaries can act as trapping sites. This information is vital for designing embrittlement-resistant steels.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Orientation gradients and geometrically necessary dislocations in ultrafine grained dual-phase steels studied by 2D and 3D EBSD

Abstract: We study orientation gradients and geometrically necessary dislocations (GNDs) in two ultrafine grained dual-phase steels with different martensite particle size and volume fraction (24 vol.% and 38 vol.%). The steel with higher martensite fraction has a lower elastic limit, a higher yield strength and a higher tensile strength. These effects are attributed to the higher second phase fraction and the inhomogeneous transformation strain accommodation in ferrite. The latter assumption is analyzed using high-resolution electron backscatter diffraction (EBSD). We quantify orientation gradients, pattern quality and GND density variations at ferrite–ferrite and ferrite–martensite interfaces. Using 3D EBSD, additional information is obtained about the effect of grain volume and of martensite distribution on strain accommodation. Two methods are demonstrated to calculate the GND density from the EBSD data based on the kernel average misorientation measure and on the dislocation density tensor, respectively. The overall GND density is shown to increase with increasing total martensite fraction, decreasing grain volume, and increasing martensite fraction in the vicinity of ferrite.

Bimetallic Nanocrystals: Syntheses, Properties, and Applications

Abstract: Achieving mastery over the synthesis of metal nanocrystals has emerged as one of the foremost scientific endeavors in recent years. This intense interest stems from the fact that the composition, size, and shape of nanocrystals not only define their overall physicochemical properties but also determine their effectiveness in technologically important applications. Our aim is to present a comprehensive review of recent research activities on bimetallic nanocrystals. We begin with a brief introduction to the architectural diversity of bimetallic nanocrystals, followed by discussion of the various synthetic techniques necessary for controlling the elemental ratio and spatial arrangement. We have selected key examples from the literature that exemplify critical concepts and place a special emphasis on mechanistic understanding. We then discuss the composition-dependent properties of bimetallic nanocrystals in terms of catalysis, optics, and magnetism and conclude the Review by highlighting applications that h...