A5077994119- Photonic and Optical Devices
- Nanowire Synthesis and Applications
- Silicon Nanostructures and Photoluminescence
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and devices
- Photonic Crystals and Applications
- Advanced Fiber Optic Sensors
- Semiconductor Lasers and Optical Devices
- Thin-Film Transistor Technologies
- Electronic and Structural Properties of Oxides
- Semiconductor materials and interfaces
- Organic Electronics and Photovoltaics
- Quantum Dots Synthesis And Properties
- Advanced Photonic Communication Systems
- Mechanical and Optical Resonators
- Quantum, superfluid, helium dynamics
- Advanced Semiconductor Detectors and Materials
- Quantum and electron transport phenomena
Eindhoven University of Technology
2017-2024
Schott (Germany)
2023-2024
Technical University of Munich
2023-2024
Advanced Materials and Devices (United States)
2021
Delft University of Technology
2016
Group IV semiconductor optoelectronic devices are now possible by using strain-free direct band gap GeSn alloys grown on a Ge/Si virtual substrate with Sn contents above 9%. Here, we demonstrate the growth of Ge/GeSn core/shell nanowire arrays incorporation up to 13% and without formation clusters. The geometry promotes strain relaxation in Ge0.87Sn0.13 shell limits structural defects. This results room-temperature photoluminescence centered at 0.465 eV enhanced absorption 98%. Therefore,...
The simultaneous control of lattice strain, composition, and microstructure is crucial to establish high-quality, direct bandgap GeSn semiconductors. Herein, we demonstrate that multilayer growth with a gradual increase in composition an effective process minimize bulk surface segregation eliminate phase separation during epitaxy yielding uniform Sn incorporation up ∼18 at. %. Detailed atomistic studies using atom probe tomography reveal the presence abrupt interfaces between monocrystalline...
Highly oriented Ge0.81Sn0.19 nanowires have been synthesized by a low-temperature chemical vapor deposition growth technique. The nanostructures form self-seeded vapor–liquid–solid mechanism. In this process, liquid metallic Sn seeds enable the anisotropic crystal and act as sole source of for formation metastable Ge1–xSnx semiconductor material. strain relaxation lattice mismatch ε = 2.94% between Ge (111) substrate constant composition is confined to transition zone <100 nm. contrast,...
The growth of Sn-rich group-IV semiconductors at the nanoscale can enrich understanding fundamental properties metastable GeSn alloys. Here, we demonstrate effect conditions on morphology and composition Ge/GeSn core/shell nanowires by correlating experimental observations with a theoretical interpretation based multiscale approach. We show that cross-sectional changes from hexagonal to dodecagonal upon increasing supply Sn precursor. This transformation strongly influences distribution as...
By independently engineering strain and composition, this work demonstrates investigates direct band gap emission in the mid-infrared range from GeSn layers grown on silicon. We extend room-temperature wavelength above ~4.0 {\mu}m upon post-growth relaxation with uniform Sn content of 17 at.%. The fundamental mechanisms governing optical are discussed based temperature-dependent photoluminescence, absorption measurements, theoretical simulations. Regardless these analyses confirm that...
Recently synthesized hexagonal group IV materials are a promising platform to realize efficient light emission that is closely integrated with electronics. A high crystal quality essential assess the intrinsic electronic and optical properties of these unaffected by structural defects. Here, we identify previously unknown partial planar defect in type I3 basal stacking fault investigate its properties. Electron microscopy atomistic modeling used reconstruct visualize this terminating...
Hexagonal Si
Quantum gases consisting of species with distinct quantum statistics, such as Bose-Fermi mixtures, can behave in a fundamentally different way than their unmixed constituents. This makes them an essential platform for studying emergent many-body phenomena mediated interactions and unconventional pairing. Here, we realize equilibrium mixture bilayer electron system implemented WS$_{2}$/WSe$_{2}$ moir\'e heterobilayer strong Coulomb coupling to nearby moir\'e-free WSe$_{2}$ monolayer. Absent...
Hexagonal crystal phase Si1-xGex is a direct bandgap semiconductor for x>70%. We observe tunable light emission 1.8-3.5 μm at 4K. amplified spontaneous as well coherent Hex-Ge.
Hexagonal SiGe has been theoretically shown to feature a tunable direct bandgap in the range 0.4-0.8eV. We study arrays of site-selectively grown Si_(1-x)-Ge_x nanowires (NWs) using crystal transfer method which wurtzite GaP core NWs are used as template for growth. Our approach opens up routes towards photonic band-edge lasers group-IV NWs. Low-temperature µPL studies NW-arrays reveal strong emission at 0.395eV and linear power dependence weak excitation levels (P_ex~0.01-1kW/cm^2). For...
The effect of strain and composition on the opto-electronic properties (Si)GeSn semiconductors across 4-300K temperature range will be discussed to pave way for future device operation up 4.5 pm wavelengths.
Light emission from Si, would allow integration of electronic and optical functionality in the main electronics platform technology, but this has been impossible due to indirect band gap Si. In talk I will discuss 2 different approaches, using unique properties nanowires, realize light Si-based compounds.
Hexagonal Ge has been predicted to have a long 20µs lifetime. A Lasher-Stern-Würfel fit of the photoluminescence spectrum provides an estimation for lifetime and optical matrix element instead showing nanosecond radiative
Hexagonal SiGe is a direct bandgap semiconductor due to zone folding. A Lasher- Stern-Wurfel fit of the photoluminescence spectrum unambiguously confirms band- to-band recombination. The transition matrix elements are large since translational symmetry broken.
Hexagonal SiGe is shown to feature a direct bandgap with radiative strength comparable InP. Surprisingly, it features temperature independent emission strength, thus promising silicon compatible laser tunable from 1.8 3.5 pm.
Sn-containing group IV semiconductors (Si)GeSn represent a versatile platform to implement variety of Si-compatible photonic, optoelectronic, and photovoltaic devices operating from SWIR MIR wavelengths. This class provides two degrees freedom, strain composition, tailor the band structure lattice parameter thus enabling heterostructures low-dimensional systems on Si substrate.[1] In this presentation, recent progress in epitaxial growth opto-electronic properties metastable with Sn contents...