A5002150978- Superconducting and THz Device Technology
- Semiconductor Quantum Structures and Devices
- Thermal properties of materials
- Microwave Engineering and Waveguides
- Advanced Thermoelectric Materials and Devices
- Thermal Radiation and Cooling Technologies
- Terahertz technology and applications
- Gyrotron and Vacuum Electronics Research
- Acoustic Wave Resonator Technologies
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Radio Frequency Integrated Circuit Design
- Semiconductor Lasers and Optical Devices
- CCD and CMOS Imaging Sensors
- Energy Harvesting in Wireless Networks
- Heat Transfer and Boiling Studies
- Antenna Design and Analysis
- Semiconductor materials and devices
- Silicon Carbide Semiconductor Technologies
- 3D IC and TSV technologies
- Advanced Antenna and Metasurface Technologies
- Full-Duplex Wireless Communications
- Advanced Thermodynamics and Statistical Mechanics
- Thermography and Photoacoustic Techniques
- Spectroscopy and Laser Applications
De Montfort University
2011-2017
The length of the transit region a Gunn diode determines natural frequency at which it operates in fundamental mode—the shorter device, higher operation. long-held view on design is that for functioning device minimum about 1.5 μm, limiting devices to mode operation frequencies roughly 60 GHz. Study these by more advanced Monte Carlo techniques simulate ballistic transport and electron-phonon interactions govern behaviour, offers new lower bound 0.5 already being approached experimental...
We present the first results of a planar Gunn diode made in In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.53</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.47</sub> As on an InP substrate, operating at fundamental frequency up to 164 GHz. For 120-μm-wide device with 1.3- μm active channel length, highest power achieved was approximately -10 dBm
When biased in the negative differential resistance regime, electroluminescence (EL) is emitted from planar GaAs heterostructure Gunn diodes. This EL due to recombination of electrons device channel with holes that are generated by impact ionisation when domains reach anode edge. The forms non-uniform patterns whose intensity shows short-range variations direction parallel contacts and decreases along towards cathode. paper employs Monte Carlo models, conjunction experimental data, analyse...
ABSTRACT This letter reports the highest fundamental oscillator operating frequency of 120 GHz for gallium arsenide (GaAs)‐based Gunn diode. The describes design, fabrication, and test aluminum (AlGaAs)/(GaAs) planar diode with an anode to cathode separation 1 μm channel width μm. was designed integrated series inductor in coplanar waveguide format. experimental results showed that oscillated at a 120.47 RF output power −9.14 dBm. is recorded GaAs‐based © 2014 Wiley Periodicals, Inc....
The paper describes the planar Gunn diode, which is a device well suited to provide milli-metric and tera-hertz sources using microwave monolithic integrated circuit technologies. Different electrode geometries are described along with DC, RF thermal characterisation. To realize high frequency there requirement for resonators, will describe both radial new diamond shaped geometries.
This letter describes the use of a novel micro-particle sensor (~3 μm diameter) and infra-red microscopy to measure temperature profile within active channel (typically 3-μm length 120-μm width) planar Gunn diodes. The method has enabled detailed measurements showing an asymmetrical along width these devices. suggests similar behavior in current density, which may contribute lower than expected RF output power.
ABSTRACT In this article, the resonant frequency and quality factor of a novel coplanar waveguide (cpw) diamond‐shaped resonator were analyzed using advanced design system‐2009 momentum model software. The diamond was compared with cpw radial stub on gallium arsenide (GaAs); work indicated that had smaller physical size higher (Q) at millimetric wave frequencies. Experimentally measured resonators fabricated GaAs in good agreement simulated results. © 2014 Wiley Periodicals, Inc. Microwave...
A self-consistent Ensemble Monte Carlo (EMC) model was developed to simulate the thermionic effect in heterostructure barrier coolers. The validated on an InGaAs-InGaAsP device of variable height and width, producing good quantitative agreement with previous literature results. operation cooler found be a complex intricate process depending field, conduction band details structure. When applied GaAs-AlGaAs micro-cooler there experimental Importantly, very small alterations structure were...
Analogue test structures were fabricated using the Tower Partners Semiconductor Co. CMOS 65 nm ISC process. The purpose was to characterise and qualify this process optimise sensor for next generation of Monolithic Active Pixels Sensors high-energy physics. technology explored in several variants which differed by: doping levels, pixel geometries pitches (10-25 $\mu$m). These have been tested following exposure varying levels irradiation up 3 MGy $10^{16}$ 1 MeV n$_\text{eq}$ cm$^{-2}$. Here...
ABSTRACT Miniature aluminium gallium arsenide/gallium arsenide (AlGaAs/GaAs) coolers were fabricated on wafer, enabling different contact geometries to be realized in the same process run. To individually DC bias microcooler, microprobes used leading thermal loading of cooler. A simple experimental technique was developed verify temperature difference (ΔT) between cold cathode and hot anode contacts is due cooling rather than heating © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett...
The packing density and power capacity of integrated electronics is increasing resulting in higher thermal flux densities. Improved management techniques are required one approach to include thermoelectric coolers as part the circuit. An analysis will be described showing that supporting substrate have a large influence on cooling cooler. In particular, for materials with low ZT figure merit (for example gallium arsenide (GaAs) based compounds) substantially thinned obtain cooling, which may...
A novel gallium arsenide (GaAs) based micro-cooler design, previously analysed both experimentally and by an analytical Heat Transfer (HT) model, has been simulated using a self-consistent Ensemble Monte Carlo (EMC) model for more in depth analysis of the thermionic cooling device. The best fit to experimental data was found used conjunction with HT estimate cooler-contact resistance. results from EMC indicated that power device is highly dependent on charge distribution across leading...
The paper describes the planar Gunn diode characterisation and preliminary design of coplanar waveguide integrated resonators for fundamental harmonic oscillator operation.
Conventional infrared (IR) thermal microscopy is a widely used technique for measuring the performance of electronic devices. The can be to rapidly generate wide area, 2D maps, example, on microwave monolithic integrated circuit (MMIC) structures. captured IR images will provide good approximate temperature distribution, however, they may suffer from errors, which occur when low emissivity metals and optically transparent semiconductor materials are studied. Although high coating applied...