A5041341998- Nanowire Synthesis and Applications
- 2D Materials and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and interfaces
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- MXene and MAX Phase Materials
- Graphene research and applications
- GaN-based semiconductor devices and materials
- Perovskite Materials and Applications
- Semiconductor materials and devices
- Topological Materials and Phenomena
- ZnO doping and properties
- Electronic and Structural Properties of Oxides
- Surface and Thin Film Phenomena
- Quantum and electron transport phenomena
- Machine Learning in Materials Science
- Photonic and Optical Devices
- Silicon Nanostructures and Photoluminescence
- Plasmonic and Surface Plasmon Research
- Ga2O3 and related materials
- Thin-Film Transistor Technologies
- Advanced Materials Characterization Techniques
- Luminescence and Fluorescent Materials
Delft University of Technology
2015-2025
QuTech
2017-2025
Eindhoven University of Technology
2015-2017
École Polytechnique Fédérale de Lausanne
2011-2016
University of Oxford
2015
Clarendon College
2015
Science Oxford
2015
Universitat de Barcelona
2009-2011
Institut de Ciència de Materials de Barcelona
2011
Schott (Germany)
2011
The structural and optical properties of three different kinds GaAs nanowires with 100% zinc-blende structure an average 30% 70% wurtzite are presented. A variety shorter longer segments or crystal phases observed by transmission electron microscopy in the nanowires. Sharp photoluminescence lines emission energies tuned from 1.515 eV down to 1.43 when percentage is increased. downward shift peaks can be understood carrier confinement at interfaces, quantum wells random short period...
Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They offered an exceptional testbed for superconductivity, leading the realization of hybrid systems combining macroscopic properties superconductors with possibility control charges down a single electron. These advances brought semiconductor forefront efforts realize topological superconductivity Majorana modes. A prime challenge benefit from...
Polarization dependent Raman scattering experiments realized on single GaAs nanowires with different percentages of zinc-blende and wurtzite structure are presented. The selection rules for the special case found discussed. In zinc-blende, transversal optical mode E1(TO) at 267 cm-1 exhibits highest intensity when incident analyzed polarization parallel to nanowire axis. This is a consequence geometry dielectric mismatch environment, in quite good agreement rules. We also find consistent...
A novel method for the direct correlation at nanoscale of structural and optical properties single GaAs nanowires is reported. Nanowires consisting 100% wurtzite presenting zinc-blende/wurtzite polytypism are investigated by photoluminescence spectroscopy transmission electron microscopy. The consistent with a band gap 1.5 eV. In polytypic nanowires, it shown that regions predominantly composed either zinc-blende or phase show emission close to bulk gap, while nonperiodic superlattice phases...
Silicon, arguably the most important technological semiconductor, is predicted to exhibit a range of new and interesting properties when grown in hexagonal crystal structure. To obtain pure silicon great challenge because it naturally crystallizes cubic Here, we demonstrate fabrication stable evidenced by structural characterization. In our approach, transfer structure from template gallium phosphide nanowire an epitaxially shell, such that formed. The typical ABABAB... stacking shown...
Topological superconductivity is a state of matter that can host Majorana modes, the building blocks topological quantum computer. Many experimental platforms predicted to show such rely on proximity-induced superconductivity. However, accessing properties requires an induced hard superconducting gap, which challenging achieve for most material systems. We have systematically studied how interface between InSb semiconductor nanowire and NbTiN superconductor affects properties. Step by step,...
Plasma-enhanced low temperature growth (<300 °C) of silicon nanowires (SiNWs) and hierarchical structures via a vapor–liquid–solid (VLS) mechanism are investigated. The SiNWs were grown using tin indium as catalysts prepared by in situ H2 plasma reduction SnO2 ITO substrates, respectively. Effective at temperatures 240 °C have been achieved, while is found to be more ideal than achieving better size density control the SiNWs. Ultra-thin (4–8 nm) silica nanowires, sprouting from dendritic...
Semiconductor nanowire arrays are reproducible and rational platforms for the realization of high performing designs light emitting diodes photovoltaic devices. In this paper we present an overview growth challenges III-V obtained by molecular beam epitaxy design on silicon solar cells. While InAs tends to grow in a relatively straightforward manner patterned (111)Si substrates, GaAs nanowires remain more challenging; success depends cleaning steps, annealing procedure, pattern mask...
Molecular beam epitaxy is used for the synthesis of catalyst-free GaAs nanowires and related quantum heterostructures. After growth nanowire core, conditions are changed in situ towards standard MBE planar order to obtain heterostructures on facets nanowires. Depending orientation, different geometries obtained. This method fully characterized by high resolution scanning transmission electron microscopy Z-contrast tomography. The also tuned optimization homogeneity optical properties....
With the continued maturation of III-V nanowire research, expectations material quality should be concomitantly raised. Ideally, nanowires integrated on silicon entirely free extended planar defects such as twins, stacking faults, or polytypism, position-controlled for convenient device processing, and gold-free compatibility with standard complementary metal-oxide-semiconductor (CMOS) processing tools. Here we demonstrate large area vertical GaAsxSb1-x arrays grown (111) by molecular beam...
Reliable doping is required to realize many devices based on semiconductor nanowires. Group III–V nanowires show great promise as elements of high-speed optoelectronic devices, but for such applications it important that the electron mobility not compromised by inclusion dopants. Here we GaAs can be n-type doped with negligible loss mobility. Molecular beam epitaxy was used fabricate modulation-doped Al0.33Ga0.67As shells contained a layer Si We identify presence from high-angle annular dark...
Self-catalyzed growth of axial In(x)Ga(1-x)As/GaAs heterostructures has been realized by molecular beam epitaxy. The the wires is achieved from gallium/indium alloy droplets that are nucleated in situ. By variation In/Ga flux during it was possible to vary effective indium content up x = 5%, as deduced photoluminescence measurements. We have analyzed dependence concentration on conditions and present a simple model for growth. grown with method presented were spatially mapped along confocal...
Silicon nanowires have been grown with gallium as catalyst by plasma enhanced chemical vapor deposition. The morphology and crystalline structure has studied electron microscopy Raman spectroscopy a function of growth temperature thickness. We observe that the quality wires increases at which they synthesized. direction found to vary between , depending on both Gallium end nanowires, expected from vapor–liquid–solid mechanism. These results represent good progress towards finding alternative...
The ability of core–shell nanowires to overcome existing limitations heterostructures is one the key ingredients for design next generation devices. This requires a detailed understanding mechanism strain relaxation in these systems order eliminate strain-induced defect formation and thus boost important electronic properties such as carrier mobility. Here we demonstrate how hole mobility [110]-oriented Ge–Si can be substantially enhanced thanks realization large band offset coherent system,...
Localized plasmon resonances in 2D transition metal dichalcogenides (TMDs) offer a powerful means to enhance light–matter interactions at the nanoscale, making them ideal candidates for advanced optoelectronic applications. However, disentangling complex plasmonic these materials, especially low‐energy regime, presents significant challenges. Herein, localized chemical vapor deposition‐grown tungsten disulfide (WS 2 ) nanotriangles, using combination of spectral analysis and simulation...
We investigate the emission properties of excitons in GaAs nanowires containing quantum disks formed by structural alternation between zinc-blende and wurtzite phases, means temperature-dependent photoluminescence. At 10 K from an ensemble is distributed a band full width at half maximum \ensuremath{\sim}30 meV, whereas linewidth for single disk 700 \ensuremath{\mu}eV. While exhibits S-shaped temperature dependence, follows dependence gap over whole range. This indicates that intradisk...
The three-dimensional carrier confinement in GaN nanodiscs embedded GaN/Al${}_{x}$Ga${}_{1\ensuremath{-}x}$N nanowires and its effect on their photoluminescence properties is analyzed for Al concentrations between $x=0.08$ 1. Structural analysis by high-resolution transmission electron microscopy reveals the presence of a lateral Al${}_{x}$Ga${}_{1\ensuremath{-}x}$N shell due to composition-dependent growth rate barrier material. structural are used as input parameters numerical simulations...
GaAs/Al-GaAs core-shell nanowires fabricated by molecular beam epitaxy contain quantum confining structures susceptible of producing narrow photoluminescence (PL) and single photons. The nanoscale chemical mapping these is analyzed in 3D atom probe tomography (APT). study allows us to confirm that Al atoms tend segregate within the AlGaAs shells towards vertices hexagons defining nanowire cross section. We also find strong alloy fluctuations remaining shell, leading occasionally formation...
Edge structures are low-dimensional defects unavoidable in layered materials of the transition metal dichalcogenides (TMD) family. Among various types such structures, armchair (AC) and zigzag (ZZ) edge most common. It has been predicted that presence intrinsic strain localized along these edges can have direct implications for customization their electronic properties. However, pinning down relation between local structure properties at is challenging. Here, we quantify field arises MoS2...
Majorana Zero Modes (MZMs) are prime candidates for robust topological quantum bits, holding a great promise computing. Semiconducting nanowires with strong spin orbit coupling offers promising platform to harness one-dimensional electron transport physics. Demonstrating the nature of MZMs relies on braiding, accomplished by moving around each other in certain sequence. Most proposed braiding circuits require nanowire networks minimal disorder. Here, electronic across junction between two...