A5086956244- Microwave Engineering and Waveguides
- Radio Frequency Integrated Circuit Design
- GaN-based semiconductor devices and materials
- Advanced Optical Sensing Technologies
- CCD and CMOS Imaging Sensors
- Millimeter-Wave Propagation and Modeling
- Ocular and Laser Science Research
- Antenna Design and Analysis
- Terahertz technology and applications
- Advanced Fluorescence Microscopy Techniques
- Superconducting and THz Device Technology
- Silicon Carbide Semiconductor Technologies
- Semiconductor materials and devices
- Advancements in PLL and VCO Technologies
- Advanced Fiber Laser Technologies
- Induction Heating and Inverter Technology
University of Glasgow
2016-2022
Cardiff University
2019-2020
In this article, we report the optimization of ohmic contact formation on AlGaN/GaN low-resistivity silicon. For achieving this, a strategy uneven was introduced through patterned etching substrate under contact. Various pattern designs (holes, horizontal lines, vertical grid) and varied etch depth (above below 2-D electron gas) were investigated. Furthermore, study planar nonplanar metallization Compared to traditional fabrication strategy, observed reduced resistance from 0.35 0.27 Ω · mm...
In this paper, we have demonstrated a viable microstrip array patch antenna technology for the first time on GaN-on-low resistivity silicon (LR-Si) substrates (ρ <; 40 Ω.cm) at H-band frequencies (220-325 GHz). The developed is compatible with standard MMIC no requirement high temperature processes. To mitigate losses presented by substrate and to enhance performance of integrated THz frequencies, driven shielded nitride gold layer in addition benzocyclobutene (BCB). 4×1 showed measured...
In this work a novel ultra-low loss transmission media for RF GaN-on-low-resistivity silicon (LR-Si) substrates (σ <; 40 Ω.cm) has been successfully demonstrated. The developed shielded-microstrip lines achieve comparable performance to those on semi-insulating (SI) GaAs with of 0.9 dB/mm frequencies up 67 GHz. Line was further enhanced by additional elevation the using air-bridge technology above 5 μm layer benzocyclobutene (BCB) shielded metalized ground planes. Transmission 0.6 GHz...
In this paper we demonstrate various configurations of THz microstrip antenna on GaN-on low resistivity silicon substrates (ρ <; 40 Ω.cm). To reduce the losses caused by substrate and to enhance performance, driven patch is shielded a ground plane nitride, with BCB as inset layer between them. Second (elevated patch) suspended in air using gold posts, which makes design stack configuration. Here, study performances has been represented changing shape rectangular circular, optimising height...
In this paper we demonstrate a THz microstrip stack antenna on GaN-on-low resistivity silicon substrates (ρ <; 40 Ω.cm). To reduce losses caused by the substrate and to enhance performance of integrated at frequencies, driven patch is shielded nitride gold in addition layer benzocyclobutene (BCB). A second circular elevated air using posts, making design configuration. The demonstrated shows measured resonance frequency agreement with modeling 0.27 S11 as low -18 dB was obtained....
We demonstrate a quadrature branch-line coupler operating at 90 GHz on GaN-on-low resistivity silicon substrates (ρ <; 40 Ω.cm). To reduce the losses offered by low-resistivity GHz, shielding technique is used where substrate covered ground plane (Al metal). SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> dielectric of thickness 10 μm as spacer between top metal and to further improve performance coupler. Measured results showed...
Single-photon avalanche diode (SPAD) detectors are of significant interest for numerous applications, including light detection and ranging (LIDAR), quantum technologies such as quantum-key distribution information processing. Here we present a record low noise-equivalent-power (NEP) Ge-on-Si SPADs using pseudo-planar design, showing high efficiency in the short-wave infrared; spectral region which is key hugely beneficial LIDAR. These devices can leverage benefits Si layers, with lower...
In this work, a viable passive components and transmission media technology is presented for THz-Monolithic Integrated Circuits (THz-MIC). The developed based on shielded microstrip (S-MS) employing standard monolithic microwave integrated circuit compatible process. S-MS uses 5-µm layer of benzocyclobutene (BCB) metalized ground plates avoiding any substrate coupling effects. An insertion loss less than 3 dB/mm was achieved frequencies up to 750 GHz. To prove the effectiveness technology,...
Semiconductor based single-photon avalanche diode (SPAD) detectors are widely used in quantum technology applications, which focus on the arrival time of single photons. Using germanium as absorption region a Separate Absorption and Multiplication design solves operating limitation beyond spectrum range silicon, i.e. typically at wavelength ~ 1000 nm. Our first-generation planar geometry Ge-on-Si diodes utilised nm Germanium showed extremely low noise-equivalent-power 7.7 × 10−17 WHz−½ 1310...
We present a pseudo-planar geometry 26µm diameter Ge-on-Si single-photon avalanche diode (SPAD) detector with temperature insensitive single photon detection efficiency of 29.4% at 1310nm wavelength for applications including free-space LIDAR. A record low dark count rate 104 counts/s 125K an excess bias 6.6% is demonstrated, temporal jitter reaching 134ps. The noise-equivalent power measured to be 7.7x10-17WHz-12 which 2 orders magnitude reduction when compared comparable 25µm mesa devices....
Single-Photon Avalanche Diode (SPAD) detectors are of significant interest for a range applications [1] , in particular quantum technologies (e.g. quantum-key distribution, information processing), and light detection ranging (LIDAR) defence, terrain mapping, autonomous vehicles. These either require, or benefit from, operation at wavelengths the short-wave infrared (SWIR). Previous SWIR single-photon LIDAR has typically used InGaAs/InP SPAD detector technology, which relatively low...