A5084302737- Semiconductor materials and devices
- Ferroelectric and Negative Capacitance Devices
- Advancements in Semiconductor Devices and Circuit Design
- 2D Materials and Applications
- MXene and MAX Phase Materials
- Advanced Memory and Neural Computing
- Graphene research and applications
- Advanced X-ray and CT Imaging
- Medical Imaging Techniques and Applications
- Radiation Dose and Imaging
- Electrowetting and Microfluidic Technologies
- Integrated Circuits and Semiconductor Failure Analysis
- Particle accelerators and beam dynamics
- Liquid Crystal Research Advancements
- Particle Accelerators and Free-Electron Lasers
- Advanced MRI Techniques and Applications
- Interconnection Networks and Systems
- Digital Radiography and Breast Imaging
- Gyrotron and Vacuum Electronics Research
- Polymer Surface Interaction Studies
- Molecular Junctions and Nanostructures
- Innovative Microfluidic and Catalytic Techniques Innovation
- VLSI and Analog Circuit Testing
- Advanced Radiotherapy Techniques
- Advanced Materials and Mechanics
Stanford University
1975-2025
Intel (United Kingdom)
2025
University of Waterloo
2020-2024
Harvard University
2022-2024
Lawrence Livermore National Laboratory
2022
Princeton University
2022
Stanford Synchrotron Radiation Lightsource
1975
SLAC National Accelerator Laboratory
1975
Strain engineering can modulate the properties of two-dimensional (2D) semiconductors for electronic and optoelectronic applications. Recent theory experiments have found that uniaxial tensile strain improve electron mobility monolayer MoS
Liquid crystal surfaces enable manipulation of liquid mobility and cargo release via temperature, electrolytes, light.
Ambidirectionality, which is the ability of structural elements to move beyond a reference state in two opposite directions, common nature. However, conventional soft materials are typically limited single, unidirectional deformation unless complex hybrid constructs used. We exploited combination mesogen self-assembly, polymer chain elasticity, and polymerization-induced stress design liquid crystalline elastomers that exhibit mesophases: chevron smectic C (cSmC) A (SmA). Inducing...
When transistor gate insulators have nanometer-scale equivalent oxide thickness (EOT), the capacitance (CG) becomes smaller than (Cox) due to quantum and charge centroid of channel. Here, we study monolayer MoS2 as a prototypical two-dimensional (2D) channel while considering spatial variations in potential, density, density states. At 0.5 nm EOT, is its capacitance, limiting single-gated CG an n-type between 63% 78% Cox, for overdrive voltages 1 V. Despite these limitations, dual-gated...
Low-power transistors based on two-dimensional (2D) semiconductors require ultrathin gate insulators, whose atomic layer deposition (ALD) has been difficult without adequate surface preparation. Here, we achieve sub-1 nm equivalent oxide thickness (EOT) monolayer MoS2 using HfO2 and a simple, commonly available Si seed. We first investigate six seed candidates (Si, Ge, Hf, La, Gd, Al2O3) find that only Ge cause no measurable damage to the MoS2. With these, build ALD of top-gate dielectric...
Two-dimensional (2D) materials are promising for beyond-silicon logic due to their ultrathin bodies atomically thin channels. A key challenge lies in doping, enable high-performance devices with a predictable and tunable threshold voltage (VT), while retaining switching behavior. In this work, we explore n-doping monolayer MoS2 solvents of varying polarity both enhance transistor performance understand how impact the VT. We find that solvent predictably shifts VT when states available near...
Various forms of ecological monitoring and disease diagnosis rely upon the detection amphiphiles, including lipids, lipopolysaccharides, lipoproteins, at ultralow concentrations in small droplets. Although assays based on droplets’ wettability provide promising options some cases, their reliance measurements surface bulk properties whole droplets (e.g., contact angles, tensions) makes it difficult to monitor trace amounts these amphiphiles within small-volume samples. Here, we report a...
Low-dimensional (low-D) semiconductors such as carbon nanotubes (CNTs) and 2-D materials are promising channel for nanoscale field-effect transistors (FETs) due to their superior electrostatic control. However, classical scale length theory (SLT) does not incorporate the effect of extensions, which becomes crucial thin channels (< 10 nm) short gate lengths. Here, we extend SLT by introducing two boundary coupling parameters, describe impact drain biases on source- drain-channel junction...
Two-dimensional (2D) electronics require low contact resistance (
Field-effect transistors (FETs) based on two-dimensional (2D) semiconductors must have ultrathin gate dielectrics in order to achieve low voltage operation. Here we conformal HfO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> monolayer MoS with the aid of an AlO xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> seed layer deposited by "nanofog," a temperature process at 50 °C. We study uniformity nanofog as function its deposition...
A next-generation interventional guidance system is proposed that will enable intraprocedural access to both x-ray and magnetic resonance imaging (MRI) modalities. This closed bore XMR (CBXMR) comprised of a conventional radiographic rotating anode tube direct conversion flat panel detector on gantry positioned adjacent the MRI. To assess feasibility such system, we have investigated degree compatibility between components For effect motor was negligible regardless orientation with respect...
Two-dimensional (2D) transition metal dichalcogenides (TMDs) with native high-κ oxides have presented a new avenue towards the development of next-generation ultra-scaled field-effect transistors (FETs). These materials been experimentally shown to form natively compatible oxide layer high dielectric constant, which can help scale down both transistor size and supply voltage. We present material device performance study into use several these – namely HfS2, HfSe2, ZrS2, ZrSe2 as channels in...
The single beam and colliding performance of the SLAC electron-positron storage ring SPEAR II is described. sevenfold increase in harmonic number comparison to I has made significant changes behavior. Strong synchrobetatron resonances a new transverse instability are observed our first studies these phenomena described, Measurements on current dependent bunch lengthening presented.
2-D semiconductors show great promise to serve as channel materials in next-generation field-effect transistors (FETs). The permittivity of many is anisotropic, though recent simulation works studying FETs have treated these they isotropic permittivities. Because there been no that investigate the role each element a semiconductor's anisotropic on device's performance, impact this approximation has simulation's accuracy unknown. Furthermore, performance cannot be explained using existing...
Materials scientists have developed a wide variety of anisotropic insulators that could offer avenues to separately manipulate lateral and perpendicular electric fields if implemented as the gate or spacers in field-effect transistors (FETs). However, there been no works studied how electrostatics an FET can be engineered by using insulators. We address this gap knowledge simulating metal–oxide–semiconductor FETs (MOSFETs) tunnel (TFETs) while varying in-plane out-of-plane permittivities...
Strain engineering can modulate the material properties of two-dimensional (2D) semiconductors for electronic and optoelectronic applications. Recent theory experiments have found that uniaxial tensile strain improve electron mobility monolayer MoS$_2$, a 2D semiconductor, but effects biaxial on charge transport are not well-understood in semiconductors. Here, we use flexible substrates to probe WS$_2$ MoS$_2$ transistors. This approach experimentally achieves ~2x higher on-state current...
The mobility of emerging (e.g., two-dimensional, oxide, organic) semiconductors is commonly estimated from transistor current-voltage measurements. However, such devices often experience contact gating, i.e., electric fields the gate modulate resistance during measurements, which can lead conventional extraction techniques to estimate incorrectly even by a factor >2. This error be minimized measuring transistors at high gate-source bias, |$V_\mathrm{gs}$|, but this regime inaccessible in...
Two-dimensional (2D) semiconductors are promising for low-power complementary metal oxide semiconductor (CMOS) electronics, which require ultrathin n- and p-type transistor channels. Among 2D semiconductors, WS2 is expected to have good conduction both electrons holes, but transistors been difficult realize due the relatively deep valence band presence of mid-gap states with conventional contacts. Here, we report topological semimetal NbP as electrical contacts bilayer up 5.8 microamperes...
High- κ insulators have allowed MOSFETs to obtain extremely high gate capacitances while still suppressing leakage. However, using high- increases the strength of lateral fringing fields throughout MOSFETs, thus causing fringe-induced barrier lowering (FIBL), an electrostatic short-channel effect. The use in place thin low- with same equivalent oxide thicknesses (EOTs) has, therefore, been associated a tradeoff between device's control and In this study, we nonequilibrium Green's function...
When transistor gate insulators have nanometer-scale equivalent oxide thickness (EOT), the capacitance ($C_\textrm{G}$) becomes smaller than ($C_\textrm{ox}$) due to quantum and charge centroid of channel. Here, we study monolayer MoS$_\textrm{2}$ as a prototypical two-dimensional (2D) channel while considering spatial variations in potential, density, density states. At 0.5 nm EOT, is its capacitance, limiting single-gated $C_\textrm{G}$ an n-type between 63% 78% $C_\textrm{ox}$ for...
Previously we developed a single-shot quantitative x-ray imaging (SSQI) method to perform material decomposition in by combining the use of primary modulator (PM) and dual-layer (DL) detector, where PM removes scatter from DL images while provides dual energy (DE) for (MD), which further beam hardening resulting partially attenuated regions PM. We have demonstrated concept SSQI using simulation tested its efficacy on chest phantom studies performed our tabletop system. In this work, explored...