| 1. |
- Ghasemi, Masoomeh, et al.
(författare)
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Assembling your nanowire : An overview of composition tuning in ternary III-V nanowires
- 2021
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 32:7
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Forskningsöversikt (refereegranskat)abstract
- The ability to grow defect-free nanowires in lattice-mismatched material systems and to design their properties has made them ideal candidates for applications in fields as diverse as nanophotonics, nanoelectronics and medicine. After studying nanostructures consisting of elemental and binary compound semiconductors, scientists turned their attention to more complex systems - ternary nanowires. Composition control is key in these nanostructures since it enables bandgap engineering. The use of different combinations of compounds and different growth methods has resulted in numerous investigations. The aim of this review is to present a survey of the material systems studied to date, and to give a brief overview of the issues tackled and the progress achieved in nanowire composition tuning. We focus on ternary III x III1-x V nanowires (AlGaAs, AlGaP, AlInP, InGaAs, GaInP and InGaSb) and IIIV x V1-x nanowires (InAsP, InAsSb, InPSb, GaAsP, GaAsSb and GaSbP).
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| 2. |
- Ghasemi, Masoomeh, et al.
(författare)
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Bonding in intermetallics may be deceptive – the case of the new type structure Au2InGa2
- 2014
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Ingår i: Intermetallics. - : Elsevier BV. - 0966-9795. ; 46, s. 40-44
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the crystal and the electronic structure of a new ternary phase, Au2InGa2 using powder and single crystal X-Ray Diffraction (XRD) and Stuttgart Tight Binding LMTO-ASA methods, respectively. Complementary methods including Thermo-Gravimetric Differential Thermal Analysis (TG-DTA), Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) were also employed. As a result, the complete structure was determined and the role of homoatomic and heteroatomic bonding is discussed.
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| 3. |
- Ghasemi, Masoomeh, et al.
(författare)
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Phase diagrams for understanding gold-seeded growth of GaAs and InAs nanowires
- 2017
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Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 50:13
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Tidskriftsartikel (refereegranskat)abstract
- Phase diagrams are useful tools to study the phase equilibria of nanowire materials systems because the growth of nanowires is accompanied by phase formation and phase transition. We have modeled the phase equilibria of the As-Au-Ga ternary system by means of the CALPHAD method. This method is a well-established semi-empirical technique for thermodynamic modeling in which Gibbs energy functions with free parameters are defined for all phases in a system followed by adjusting these parameters to the experimental data. Using the resulting As-Au-Ga thermodynamic database, four vertical cuts of this ternary system are calculated and all show good agreement with experiments. This ternary system is particularly useful for predicting the state of the Au seed alloys when growing GaAs nanowires and we discuss such predictions. Similar calculations are performed for Au-seeded InAs nanowires. We show that the vapor-liquid-solid (VLS) growth fails for InAs nanowires, while GaAs nanowires can grow from a liquid particle. Our calculations are in agreement with experimental data on the growth of Au-seeded GaAs and InAs nanowires.
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| 4. |
- Ghasemi, Masoomeh, et al.
(författare)
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Separation of deformable hydrogel microparticles in deterministic lateral displacement devices
- 2012
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Ingår i: Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012. - 9780979806452 ; , s. 1672-1674
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Konferensbidrag (refereegranskat)abstract
- To better understand how deformable and non-spherical particles behave in sorting devices based on deterministic lateral displacement we generate models of biological particles with tunable size, shape and mechanical properties using stop-flow lithography and we explore how these parameters play a role in our separation devices. Hollow and solid cylinders are compared with respect to their deformability and their overall behavior in the device. Future work will expand the approach to a range of particle shapes and to particles with varied hydrogel composition to independently control the mechanical properties of the material.
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| 5. |
- Ghasemi, Masoomeh, et al.
(författare)
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Size- and shape-dependent phase diagram of In-Sb nano-alloys
- 2015
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 7:41, s. 17387-17396
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Tidskriftsartikel (refereegranskat)abstract
- Nano-scale alloy systems with at least one dimension below 100 nm have different phase stabilities than those observed in the macro-scale systems due to a large surface to volume ratio. We have used the semi-empirical thermodynamic modelling, i.e. the CALPHAD method, to predict the phase equilibria of the In-Sb nano-scale systems as a function of size and shape. To calculate the size- and shape-dependent phase diagram of the In-Sb system, we have added size-dependent surface energy terms to the Gibbs energy expressions in the In-Sb thermodynamic database. We estimated the surface energies of the solution phases and of the InSb intermetallic phase using the Butler equation and DFT calculations, respectively. A melting point and eutectic point depression were observed for both nanoparticle and nanowire systems. The eutectic composition on the In-rich and Sb-rich sides of the phase diagram shifted towards higher solubility. We believe that the phase diagram of In-Sb nano-alloys is useful for an increased understanding of the growth parameters and mechanisms of InSb nanostructures.
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| 6. |
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| 7. |
- Ghasemi, Masoomeh, et al.
(författare)
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The phase equilibria in the Au-In-Ga ternary system
- 2014
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 588, s. 474-480
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Tidskriftsartikel (refereegranskat)abstract
- The phase equilibria of the Au–In–Ga system were investigated for the first time using Differential Thermal Analysis (DTA), X-Ray Diffractometry (XRD), Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM). A new ternary phase (Au2InGa2) with the hexagonal structure (P63/mmc) was discovered which melts incongruently at 394 °C. From the experimental results, several invariant reactions have been identified and discussed.
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| 8. |
- Ghasemi, Masoomeh, et al.
(författare)
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The thermodynamic assessment of the Au–In–Ga system
- 2014
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Ingår i: Journal of Alloys and Compounds. - 0925-8388. ; 600, s. 178-185
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Tidskriftsartikel (refereegranskat)abstract
- The Au–In–Ga ternary phase diagram is of importance for understanding the involved thermodynamic processes during the growth of Au-seeded III–V heterostructure nanowires containing In and Ga (e.g. Au-seeded InAs/GaAs nanowires). In this work the Au–In–Ga system has been thermodynamically modeled using the CALPHAD technique based on a recent experimental investigation of the phase equilibria in the system. As a result, a set of self-consistent interaction parameters have been optimized that can reproduce most of the experimental results.
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| 9. |
- Ghasemi, Masoomeh, et al.
(författare)
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Thermodynamic assessment and binary nucleation modeling of Sn-seeded InGaAs nanowires
- 2017
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Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248 .- 1873-5002. ; 478, s. 152-158
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Tidskriftsartikel (refereegranskat)abstract
- We have performed a thermodynamic assessment of the As-Ga-In-Sn system based on the CALculation of PHAse Diagram (CALPHAD) method. This system is part of a comprehensive thermodynamic database that we are developing for nanowire materials. Specifically, the As-Ga-In-Sn can be used in modeling the growth of GaAs, InAs, and InxGa1−xAs nanowires assisted by Sn liquid seeds. In this work, the As-Sn binary, the As-Ga-Sn, As-In-Sn, and Ga-In-Sn ternary systems have been thermodynamically assessed using the CALPHAD method. We show the relevant phase diagrams and property diagrams. They all show good agreement with experimental data. Using our optimized description we have modeled the nucleation of InxGa1−xAs in the zinc blende phase from a Sn-based quaternary liquid alloy using binary nucleation modeling. We have linked the composition of the solid nucleus to the composition of the liquid phase. Eventually, we have predicted the critical size of the nucleus that forms from InAs and GaAs pairs under various conditions. We believe that our modeling can guide future experimental realization of Sn-seeded InxGa1−xAs nanowires.
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| 10. |
- Ghasemi, Masoomeh, et al.
(författare)
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Thermodynamic Assessment of the As-Zn and As-Ga-Zn Systems
- 2015
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 638, s. 95-102
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Tidskriftsartikel (refereegranskat)abstract
- We have performed a thermodynamic assessment of the As-Zn and As-Ga-Zn systems. The systems are assessed based on the CALPHAD method and using available first principles and experimental data. Using the optimized set of parameters found in this work, the calculated As-Zn binary phase diagram, isoplethal sections and the monovariants lines of the As-Ga-Zn ternary system are presented. The comparison of the calculated diagrams with the experimental and first principles data shows good agreement.
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