A5013514091- Semiconductor Quantum Structures and Devices
- Photonic and Optical Devices
- Spectroscopy and Laser Applications
- Semiconductor Lasers and Optical Devices
- Quantum and electron transport phenomena
- Advanced Photonic Communication Systems
- Atmospheric Ozone and Climate
- Terahertz technology and applications
- Advanced Fiber Laser Technologies
- Photonic Crystals and Applications
- Advanced Fiber Optic Sensors
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and devices
- Semiconductor materials and interfaces
- Laser Design and Applications
- GaN-based semiconductor devices and materials
- Nanowire Synthesis and Applications
- Silicon Nanostructures and Photoluminescence
- Optical Network Technologies
- Advanced Semiconductor Detectors and Materials
- Quantum Dots Synthesis And Properties
- Quantum Information and Cryptography
- Neural Networks and Reservoir Computing
- Quantum Mechanics and Non-Hermitian Physics
- Surface and Thin Film Phenomena
University of Leeds
2016-2025
Nanyang Technological University
2022
CEA LETI
2018
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2018
Forschungszentrum Jülich
2016-2017
KU Leuven
2017
Queensland University of Technology
2015
The University of Queensland
2015
Sheffield Hallam University
2015
University of Belgrade
1994-2010
The strong correlation between advancing the performance of Si microelectronics and their demand low power consumption requires new ways data communication. Photonic circuits on are already highly developed except for an eligible on-chip laser source integrated monolithically. recent demonstration optically pumped waveguide made from Si-congruent GeSn alloy, monolithical integration has taken a big step forward way to all-inclusive nanophotonic platform in CMOS. We present group IV microdisk...
Alloys of silicon (Si), germanium (Ge) and tin (Sn) are continuously attracting research attention as possible direct band gap semiconductors with prospective applications in optoelectronics. The property may be brought about by the alloy composition alone or combined influence strain, when an layer is grown on a virtual substrate different compositions. In search for materials, electronic structure relaxed strained Ge1−xSnx Si1−xSnx alloys, Ge Ge1−x−ySixSny, was calculated self-consistent...
Using empirical pseudopotential theory, the direct (Γ) and indirect bandgaps (L X) of unstrained crystalline SixGe1−x−ySny have been calculated over entire xy composition range. The results are presented as energy-contour maps on ternary diagrams along with a plot predicted lattice parameters. A group 0.2 to 0.6 eV direct-gap SiGeSn materials is found for variety mid-infrared photonic applications. set “slightly indirect” alloys having gap at 0.8 (but smaller L-Γ separation than in Ge)...
We demonstrate terahertz (THz) frequency imaging using a single quantum cascade laser (QCL) device for both generation and sensing of THz radiation. Detection is achieved by utilizing the effect self-mixing in QCL, and, specifically, monitoring perturbations to voltage across induced light reflected from an external object back into cavity. Self-mixing offers high sensitivity, potentially fast response, simple, compact optical design, we show that it can be used obtain high-resolution...
In this letter, we propose a heterostructure design for tunnel field effect transistors with two low direct bandgap group IV compounds, GeSn and highly tensely strained Ge in combination ternary SiGeSn alloy. Electronic band calculations show that Ge, used as channel, grown on Ge1−xSnx (x > 9%) buffer, source, becomes which significantly increases the tunneling probability. The ternaries are well suitable drain since they offer large indirect bandgap. growth of such heterostructures...
The recent observation of a fundamental direct bandgap for GeSn group IV alloys and the demonstration low temperature lasing provide new perspectives on fabrication Si photonic circuits. This work addresses progress in alloy epitaxy aiming at room lasing. Chemical vapor deposition with high Γ- to L-valley energy separation large thicknesses efficient optical mode confinement is presented discussed. Up 1 μm thick layers Sn contents up 14 at. % were grown relaxed Ge buffers, using Ge2H6 SnCl4...
Group IV photonics is on the way to be integrated with electronic circuits, making information transfer and processing faster more energy efficient.Light sources, a critical component of photonic are still in development.Here, we compare Multi-Quantum-Well (MQW) light emitting diodes (LEDs) Ge0.915Sn0.085wells Si0.1Ge0.8Sn0.1 reference Ge0.915Sn0.085homojunction LED.Material properties as well band structure calculations discussed, followed by optical investigations.Electroluminescence...
GeSn and SiGeSn are promising materials for the fabrication of a group IV laser source offering number design options from bulk to heterostructures quantum wells. Here, we investigate GeSn/SiGeSn multi wells using optically pumped effect. Three complex were grown on top 200 nm thick strain-relaxed Ge0.9Sn0.1 buffers. The lasing is investigated in terms threshold maximal operation temperature by comparing multiple well double heterostructure samples. Pumping under two different wavelengths...
Abstract The success of GeSn alloys as active material for infrared lasers could pave the way toward a monolithic technology that can be manufactured within mainstream silicon photonics. Nonetheless, operation on chip, lasing should occur at room temperature or beyond. Unfortunately, despite intense research in recent years, many hurdles have yet to overcome. An approach exploiting strain engineering induce large tensile micro‐disk made alloy with Sn content 14 at% is presented here. This...
Abstract The continued downscaling of silicon CMOS technology presents challenges for achieving the required low power consumption. While high mobility channel materials hold promise improved device performance at levels, a material system which enables both n-FETs and p-FETs, that is compatible with Si can be readily integrated into existing fabrication lines required. Here, we present performance, vertical nanowire gate-all-around FETs based on GeSn-material grown Si. p-FET...
The quantum cascade laser provides one possible method of realizing high efficiency light emitters in indirect band gap materials such as silicon. Electroluminescence results from Si/SiGe are presented demonstrating edge emission heavy-hole to transitions and light-hole transitions. In surface-normal emission, only electroluminescence is observed predicted by theory. Intersubband demonstrated at 2.9 THz (103 μm wavelength), 8.9 (33.7 μm), 16.2 (18.5 μm) the heterostructures.
The terahertz (THz) frequency quantum cascade laser (QCL) is a compact source of high-power radiation with narrow intrinsic linewidth. As such, THz QCLs are extremely promising sources for applications including high-resolution spectroscopy, heterodyne detection, and coherent imaging. We exploit the remarkable phase-stability to create swept-frequency delayed self-homodyning method both imaging materials analysis, using feedback interferometry. Using our scheme we obtain amplitude-like...
A comprehensive study of optical transitions in direct-bandgap Ge0.875Sn0.125 group IV alloys via photoluminescence measurements as a function temperature, compressive strain and excitation power is performed. The analysis the integrated emission intensities reveals strain-dependent indirect-to-direct bandgap transition, good agreement with band structure calculations based on 8-band k·p deformation potential methods. We have observed quantified Γ valley–heavy hole valley–light at low...
The design, modeling, fabrication, and characterization of single-photon avalanche diode detectors with an epitaxial Ge absorption region grown directly on Si are presented. At 100 K, a detection efficiency 4% at 1310 nm wavelength was measured dark count rate ~ 6 megacounts/s, resulting in the lowest reported noise-equivalent power for Ge-on-Si detector (1×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-14</sup> WHz...
Abstract Growth and characterization of advanced group IV semiconductor materials with CMOS‐compatible applications are demonstrated, both in photonics. The investigated GeSn/SiGeSn heterostructures combine direct bandgap GeSn active layers indirect gap ternary SiGeSn claddings, a design proven its worth already decades ago the III–V material system. Different types double multi‐quantum wells (MQWs) epitaxially grown varying well thicknesses barriers. retaining high quality those complex...
We present results on CVD growth and electro-optical characterization of Ge(0.92)Sn(0.08)/Ge p-i-n heterostructure diodes. The suitability Ge as barriers for direct bandgap GeSn active layers in different LED geometries, such double heterostructures multi quantum wells is discussed based electroluminescence data. Theoretical calculations by effective mass 6 band k∙p method reveal low barrier heights this specific structure. Best configurations offer only a maximum height electrons about 40...
In recent years much effort has been made to increase the Sn content in GeSn alloys order direct bandgap charge carrier recombination and, therefore, reach room temperature lasing. While being successful for former, of is detrimental, leading increased defect concentrations and a lower thermal budget regarding processing. this work we demonstrate strong photoluminescence enhancement low Ge0.94Sn0.06 layers by implementing tensile strain. Fitting calculated spectra reproduce our experimental...
SiGeSn holds great promise for enabling fully group-IV integrated photonics operating at wavelengths extending in the mid-infrared range. Here, we demonstrate an electrically pumped GeSn microring laser based on SiGeSn/GeSn heterostructures. The ring shape allows enhanced strain relaxation, leading to optical properties, and better guiding of carriers into optically active region. We have engineered a partial undercut further promote relaxation while maintaining adequate heat sinking. Lasing...
CMOS-compatible materials for efficient energy harvesters at temperatures characteristic on-chip operation and body temperature are the key ingredients sustainable green computing ultralow power Internet of Things applications. In this context, lattice thermal conductivity (κ) new group IV semiconductors, namely Ge1–xSnx alloys, investigated. Layers featuring Sn contents up to 14 at.% epitaxially grown by state-of-the-art chemical-vapor deposition on Ge buffered Si wafers. An abrupt decrease...
Electron transport in GaAs/AlGaAs quantum cascade lasers operating midinfrared is calculated self–consistently using an intersubband scattering model. Subband populations and carrier transition rates are all relevant electron-LO phonon electron–electron scatterings between injector/collector, active region, continuum resonance levels included. The lifetimes subband then used to evaluate current densities, injection efficiencies, backflow into the region for a range of temperatures. From...
The electronic properties of twinning boundaries, stacking faults, and a recently proposed structure, the superlattice, in group IV III-V diamond-type zinc-blende-type semiconductors are calculated discussed.