A5074746706- Photonic and Optical Devices
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and devices
- Spectroscopy and Laser Applications
- Advancements in Semiconductor Devices and Circuit Design
- Nanowire Synthesis and Applications
- Plasmonic and Surface Plasmon Research
- Silicon Nanostructures and Photoluminescence
- Advanced Optical Sensing Technologies
- Advanced Thermoelectric Materials and Devices
- Terahertz technology and applications
- Semiconductor materials and interfaces
- Semiconductor Lasers and Optical Devices
- Advanced Fiber Laser Technologies
- Mechanical and Optical Resonators
- Photonic Crystals and Applications
- Atomic and Subatomic Physics Research
- Thermal Radiation and Cooling Technologies
- Quantum and electron transport phenomena
- Advanced Fluorescence Microscopy Techniques
- CCD and CMOS Imaging Sensors
- Integrated Circuits and Semiconductor Failure Analysis
- Quantum optics and atomic interactions
- Geophysics and Gravity Measurements
- Thermal properties of materials
University of Glasgow
2015-2024
Photonics (United States)
2024
Politecnico di Milano
2015-2022
City of Glasgow College
2022
Johannes Kepler University of Linz
2022
Sapienza University of Rome
2019-2021
University of Pisa
2021
Roma Tre University
2021
Heriot-Watt University Malaysia
2020
ETH Zurich
2019
Silicon germanium (SiGe) has moved from being a research material to accounting for small but significant percentage of manufactured semiconductor devices. This is predicted increase substantially as SiGe begins be used in complementary metal oxide (CMOS) technology the future improve performance. It development Si/SiGe heterostructures which enabled band structure and strain engineering allowing many different ways conventional microelectronic device performance along with new concepts...
Midinfrared plasmonic sensing allows the direct targeting of unique vibrational fingerprints molecules. While gold has been used almost exclusively so far, recent research focused on semiconductors with potential to revolutionize devices. We fabricate antennas out heavily doped Ge films epitaxially grown Si wafers and demonstrate up 2 orders magnitude signal enhancement for molecules located in antenna hot spots compared those a bare silicon substrate. Our results set new path toward...
Abstract Single-photon detection has emerged as a method of choice for ultra-sensitive measurements picosecond optical transients. In the short-wave infrared, semiconductor-based single-photon detectors typically exhibit relatively poor performance compared with all-silicon devices operating at shorter wavelengths. Here we show new generation planar germanium-on-silicon (Ge-on-Si) avalanche diode (SPAD) infrared operation. This geometry enabled significant step-change in performance,...
Single-photon detectors with picosecond timing resolution have advanced rapidly in the past decade. This has spurred progress time-correlated single-photon counting applications, from quantum optics to life sciences and remote sensing. A variety of optoelectronic device architectures offer not only high-performance single-pixel devices but also ability scale up detector arrays extend sensitivity into short-wave infrared beyond. The advent focal plane is poised revolutionize imaging In this...
A surfactant-free solution methodology, simply using water as a solvent, has been developed for the straightforward synthesis of single-phase orthorhombic SnSe nanoplates in gram quantities. Individual are composed {100} surfaces with {011} edge facets. Hot-pressed nanostructured compacts (Eg ≈0.85 eV) exhibit excellent electrical conductivity and thermoelectric power factors (S(2) σ) at 550 K. S(2) σ values 8-fold higher than equivalent materials prepared citric acid structure-directing...
For hybrid photovoltaic-thermal collectors to become competitive with other types of solar energy converters, they must offer high performance at fluid outlet temperatures above 60 °C, as is required for space heating and domestic hot water provision, which together account nearly 50% heat demand. A roadmap presented the technological advances achieve this goal. Strategies reducing convective, radiative electrical losses elevated temperature are discussed, an experimental characterisation a...
Heavily-doped semiconductor films are very promising for application in mid-infrared plasmonic devices because the real part of their dielectric function is negative and broadly tunable this wavelength range. In work we investigate heavily n-type doped germanium epilayers grown on different substrates, in-situ $10^{17}$ to $10^{19}$ cm$^{-3}$ range, by infrared spectroscopy, first principle calculations, pump-probe spectroscopy dc transport measurements determine relation between plasma edge...
Review: The use of Si1–xGex in microelectronics production is appealing not only because it compatible with existing industrial technology used for the silicon-based microelectronics, but also induced strain caused by insertion a layer Si1–xGex(see Figure) can significantly improve their performance. and properties these new materials are reviewed.
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.
A low temperature nickel process has been developed that produces Ohmic contacts to n-type germanium with specific contact resistivities down (2.3 ± 1.8) × 10−7 Ω-cm2 for anneal temperatures of 340 °C. The resistivity is attributed the NiGe phase which was identified using electron diffraction in a transmission microscope. Electrical results indicate linear behaviour quantum mechanical tunnelling through Schottky barrier formed between alloy and heavily doped n-Ge.
The development of nanofabrication techniques for creating high aspect ratio (∼50:1) sub-10 nm silicon nanowires (SiNWs) with smooth, uniform, and straight vertical sidewalls using an inductively coupled plasma (ICP) etching process at 20 °C is reported. In particular, to improve the quality flexibility pattern transfer SiNWs, hydrogen silsesquioxane, a high-resolution, inorganic, negative-tone resist electron-beam lithography has been used as both defining patterns hard mask underneath...
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...
The thermoelectric and physical properties of superlattices consisting modulation doped Ge quantum wells inside Si1−yGey barriers are presented, which demonstrate enhancements in the figure merit, ZT, power factor at room temperature over bulk Ge, Si1−yGey, Si/Ge superlattice materials. Mobility spectrum analysis along with low measurements indicate that high factors dominated by electrical conductivity from doping. Comparison results modelling using Boltzmann transport equation scattering...
An aqueous solution method is developed for the facile synthesis of Cl‐containing SnSe nanoparticles in 10 g quantities per batch. The particle size and Cl concentration can be efficiently tuned as a function reaction duration. Hot pressing produces n‐type Cl‐doped nanostructured compacts with thermoelectric power factors optimized via control dopant concentration. This approach, combining an energy‐efficient hot pressing, provides simple, rapid, low‐cost route to high performance materials.
Germanium-on-silicon waveguides were modeled, fabricated and characterized at wavelengths ranging from 7.5 to 11 µm.Measured waveguide losses are below 5 dB/cm for both TE TM polarization reach values of ∼ 1 ≥ 10 µm the polarization.This work demonstrates experimentally first time that Ge-on-Si is a viable platform sensing in molecular fingerprint spectral region.Detailed modeling analysis presented identify various loss contributions, showing with practical techniques could be achieved...
Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on silicon substrate. This direct approach activates the plasmonic resonance of Ge and enables their use as optical antennas up to mid-infrared spectral range. The switching lasts for hundreds picoseconds until charge recombination redshifts frequency. full behavior is modeled by electrodynamic established an electron-hole regular array antennas.
We present a scanning light detection and ranging (LIDAR) system incorporating an individual Ge-on-Si single-photon avalanche diode (SPAD) detector for depth intensity imaging in the short-wavelength infrared region. The time-correlated counting technique was used to determine return photon time-of-flight target information. In laboratory demonstrations, reconstructions were made of targets at short range, using advanced image processing algorithms tailored analysis data. These measurements...
Laser cooled atoms have proven transformative for precision metrology, playing a pivotal role in state-of-the-art clocks and interferometers having the potential to provide step-change our modern technological capabilities. To successfully explore their full potential, laser cooling platforms must be translated from laboratory environment into portable, compact quantum sensors deployment practical applications. This transition requires amalgamation of wide range components expertise if an...
The design, fabrication, and characterization of a silicon nitride waveguide polarization rotator beam splitter that operate with extinction ratio (PER) ∼30 dB at the rubidium atomic transition 780 nm wavelength are demonstrated. These devices fabricated on same chip using self-aligned process for integration rib ridge structures. is based mode evolution approach adiabatic tapers demonstrates PER ≥20 over 100 bandwidth (730–830 wavelengths) an insertion loss (IL) ≤1 dB. cascaded tapered...
The integration of Ge on Si for photonics applications has reached a high level maturity: photodetectors are available the platform in foundry processes, and Si/Ge heterostructure multiple quantum-well photodiodes rapidly progressing toward light modulation. These successes result from decades development high-quality material growth integration, which, more recently, sparked an increasingly broad field photonic device research based heterostructures that extends quantum cascade lasers to...