A5010057940- Thin-Film Transistor Technologies
- Silicon and Solar Cell Technologies
- Physics of Superconductivity and Magnetism
- Iron-based superconductors research
- Silicon Nanostructures and Photoluminescence
- Semiconductor materials and devices
- Advanced Condensed Matter Physics
- Rare-earth and actinide compounds
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and interfaces
- Superconductivity in MgB2 and Alloys
- Magnetic and transport properties of perovskites and related materials
- Laser Material Processing Techniques
- Theoretical and Computational Physics
- Magnetic properties of thin films
- Superconducting Materials and Applications
- Surface Roughness and Optical Measurements
- Topological Materials and Phenomena
- Integrated Circuits and Semiconductor Failure Analysis
- Color Science and Applications
- Industrial Vision Systems and Defect Detection
- CCD and CMOS Imaging Sensors
- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Rabies epidemiology and control
University of Bristol
2018-2024
Radboud University Nijmegen
2019-2024
Bristol Robotics Laboratory
2022
Philips (India)
1987-2010
Philips (United Kingdom)
1994-2007
Philips (Finland)
1986-2000
Texas A&M University
1996
Philips (United States)
1996
Conservation and Production Research Laboratory
1996
Texas Tech University
1996
Defect impurity levels have been examined in copper-diffused p-and n-type silicon using deep level transient spectroscopy. Levels at Ev+0.09, Ev+0.23, and Ev+0.42 eV observed both types of material, although the deeper were only oberved material after post-diffusion annealing 200 °C. Associated with appearance these was another Ec−0.16 eV. This may be a further charge state center responsible for Ev+0.23 or two centers decomposition products thermally unstable complex. Luminescence...
Polycrystalline-silicon (poly-Si) thin film transistors (TFTs) have been assessed using deep level transient spectroscopy (DLTS) based on the measurement of current transients due to thermal emission carriers trapped at levels in poly-Si. Measurements were made fully hydrogenated TFTs and DLTS signal was found vary continuously between 77 K room temperature, without showing characteristic peaks normally associated with point defects single crystal Si. This demonstrates existence a continuous...
Abstract Hall effect and quantum oscillation measurements on high temperature cuprate superconductors show that underdoped compositions have small Fermi surface pockets whereas when heavily overdoped, a single much larger pocket is found. The origin of this change in electronic structure has been unclear, but may be related to the superconductivity. Here we clean overdoped single-layer Tl 2 Ba CuO 6+ δ (Tl2201) displays CDW order with remarkably long correlation length ξ ≈ 200 Å which...
Hot carrier instabilities in poly-Si thin film transistors (TFTs) are caused by high electric fields at the drain. These determined mainly abruptness of lateral n + doping profile drain and two-dimensional (2D) coupling x y components field between gate The density trapping states film, however, has a much less significant impact on field. Further, it is shown that improving properties tends to have an adverse affect hot stability. Consequently, concluded relief essential for stability...
The influence of film thickness and incident excimer laser energy density on the properties poly-Si thin transistors has been investigated a coherent pattern behavior identified which establishes controlled melt-through as key condition for achieving high quality devices. conditions were correlated with appearance large grains gave consistent results from both n- p-channel devices, carrier mobilities more than 150 80 cm2/V s, respectively, leakage currents less 2×10−14 A/μm. From study...
High-dose silicon implants have been used to preamorphize the surface of single-crystal prior implantation low-energy BF2. The preamorphization results in shallow junction formation with minimal channeling boron, but high concentrations electrically active defects are formed, leading excessive reverse bias leakage currents. Measurements current and deep-level indicated that two distinct types were important: those associated what probably complexes or clusters point located near far end...
Unambiguous and complete determination of the Fermi surface is a primary step in understanding electronic properties topical metals semi-metals, but only relatively few cases has this goal been realized. In work, we present systematic high-field quantum oscillation study up to 35 T on ZrSiS, textbook example nodal-line semimetal with linearly dispersive bands crossing energy. The topology determined unprecedented precision all pockets are identified by comparing measured angle dependence...
There is now compelling evidence that the normal state of superconducting overdoped cuprates a strange metal comprising two distinct charge sectors, one governed by coherent quasiparticle excitations, other seemingly incoherent and characterized non-quasiparticle (Planckian) dissipation. The zero-temperature superfluid density n_s(0) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>s</mml:mi></mml:msub><mml:mo...
A model based on two-dimensional (2-D) simulation, for a polysilicon thin-film transistor (poly-Si TFT) with large grains, fabricated in laser recrystallized material, is presented. The importance of differentiating between the density states traps within grains and localized at grain boundaries demonstrated. It shown that observed lack saturation TFT output characteristics arises due to effect high interface trap boundaries, whereas subthreshold slope has strong dependence grains. Only by...
One of the few undisputed facts about hole-doped high- T c cuprates is that their superconducting gap Δ has d -wave symmetry. According to ‘dirty’ BCS theory, even structural (non-magnetic) disorder can suppress Δ, transition temperature and superfluid density ρ s . The degree which latter affected by depends on nature scattering. By contrast, only sensitive total elastic scattering rate (as estimated from residual resistivity 0 ) should follow Abrikosov-Gor’kov pair-breaking formula. Here,...
Results are presented on the performance of low-temperature, short-channel polycrystalline silicon (poly-Si) thin-film transistors (TFTs), with channel length down to 0.5 μm, and scaled gate oxide thickness 20 nm. Good TFT switching characteristics were obtained, uniformity TFTs was shown have a standard deviation better then 10%, even for widths as small 4 μm. The μm been incorporated into 15-stage complementary pair metal-oxide-Si transistor ring oscillator, which, at supply voltage 3 V,...
Control of leakage current in autoregistered columnar and a solid phase crystallized poly-Si thin-film transistors (TFTs) is discussed. For n-channel TFTs, two parasitic paths, due to bulk conduction back interface conduction, have been identified. It demonstrated that these can be controlled by using sufficiently thin films low dose boron channel implants, respectively. By means, generation limited currents, with values &lt;4×10−14 A/μm width, obtained. The minimum for n- p-channel...
A new physical model based on two dimensional simulations for high quality laser re-crystallised poly-Si thin film transistors is presented. It has been shown that to adequately explain the improved subthreshold slope and lack of saturation output characteristics in these transistors, it essential distribute density defect states between traps grains alongside localised at grain boundaries. double exponential extracted (TFTs) annealed different excimer energies, using field effect...
The signature feature of the 'strange metal' state high-T
Silicon diode structures have been amorphized with 200-keV Ge+ prior to BF2 implantation. Room temperature C-V profiling revealed large concentrations of excess donor levels following epitaxial regrowth at temperatures below 800 °C. This formation and the annealing behavior is same as previously observed in Si+ preamorphized substrates. Deep-level transient spectroscopy further confirmed similarity nature spatial distribution defects produced. The conclusion drawn that fundamental...
This paper studies the magnetoresistance of FeSe1-xSx as a function sulfur doping, which goes through quantum critical point characterized by electron nematicity. The experiments show coexistence quadratic and linear form magneto-resistance. These findings suggest that low-lying electronic excitations in metal may have dual character, one is coherent
Different drain field architectures have been recently investigated to reduce field-enhanced effects in conventional self-aligned polysilicon thin-film transistor (TFT) architecture, induced by the intense electric fields at junction. Among these, gate overlapped lightly doped (GOLDD) architecture has shown be effective reducing both on and off states of TFT, without introducing appreciable series resistance effects. In this paper, we investigate electrical characteristics, on- off-regime,...
The authors show that the Hall response of electron nematic FeSe${}_{1\ensuremath{-}x}$S${}_{x}$ comprises two metal components, one which shows an anomalous 1/T temperature dependence and peaking near quantum critical point.