A5059141813- Surface and Thin Film Phenomena
- Semiconductor materials and devices
- Force Microscopy Techniques and Applications
- Semiconductor Quantum Structures and Devices
- Advanced Chemical Physics Studies
- Semiconductor materials and interfaces
- Electronic and Structural Properties of Oxides
- Nanowire Synthesis and Applications
- Molecular Junctions and Nanostructures
- Advancements in Photolithography Techniques
- Physics of Superconductivity and Magnetism
- Advanced Electron Microscopy Techniques and Applications
- Advanced Materials Characterization Techniques
- Advanced Semiconductor Detectors and Materials
- Advancements in Semiconductor Devices and Circuit Design
- Electron and X-Ray Spectroscopy Techniques
- Quantum and electron transport phenomena
- Mechanical and Optical Resonators
- Spectroscopy and Laser Applications
- nanoparticles nucleation surface interactions
- Machine Learning in Materials Science
- Ammonia Synthesis and Nitrogen Reduction
- Superconductivity in MgB2 and Alloys
- Graphene research and applications
- Nuclear Materials and Properties
Zyvex (United States)
2016-2025
The University of Texas at Dallas
2018-2022
Zygo (United States)
2015
University of Geneva
2008-2013
National Institute for Materials Science
2002-2012
Midwestern State University
2009
University of Oxford
1993-2008
National Institute of Advanced Industrial Science and Technology
2002-2003
University of California, Los Angeles
2000-2003
University of Pretoria
2003
Heteroepitaxial Ge/Si(001) growth has been investigated using in situ scanning tunneling microscopy. While at 620 K the epitaxial strain is relieved by formation of three-dimensional islands (so-called ``hut'' clusters), 690 first hut pits, having cluster shapes but with their apex pointing down. Although predicted theoretically to have lower energy than clusters, pits never observed individually before. Details and pit nucleation are also presented for time.
Bi nanolines self-assemble on Si(001) and are remarkable for their straightness length-they often more than 400 nm long, a kink in nanoline has never been observed. Through electronic structure calculations, we have found an energetically favorable these that agrees with our scanning tunneling microscopy photoemission experiments; the extremely unusual subsurface structure, comprising double core of seven-membered rings silicon. Our proposed explains all observed features nanolines, shows...
Patterned fabrication depends on selective deposition that can be best achieved with atomic layer (ALD). For the growth of TiO2 by ALD using TiCl4 and H2O, X-ray photoelectron spectroscopy reveals a marked difference in oxidized hydrogen-terminated silicon surfaces, characterized typical predictable rates observed SiO2 surfaces 185 times greater than Si(100) Si(111) surfaces. Large-scale patterning is demonstrated wet chemistry, nanometer-scale patterned through scanning tunneling microscopy...
Atomically perfect bismuth lines form on Si(001) by a selective desorption process around the temperature at which most of desorbs from epitaxial layers. The are perpendicular to silicon dimer rows; they 1 nm wide and can be hundreds long in flat surface. They utterly free kinks or other defects. In our proposed model three dimers surface replaced with two Bi dimers, rebonded missing defect between them. It is suggested that straight because kinetic reasons rather than thermodynamic ones --...
The stability of different surface reconstructions on InAs(001) is investigated theoretically and experimentally. Density-functional theory calculations predict four to be stable at chemical potentials. two dominant are the \ensuremath{\beta}2 (2\ifmmode\times\else\texttimes\fi{}4) for high As, \ensuremath{\alpha}2 low As overpressure. This trend confirmed by scanning tunneling microscopy carefully annealed surfaces. A similar behavior predicted GaAs(001).
In this work, the authors used density-functional theory methods and x-ray photoelectron spectroscopy to study chemical composition growth rate of HfO2, Al2O3, TiO2 thin films grown by in-situ atomic layer deposition on both oxidized hydrogen-terminated Si(001) surfaces. The all is found be lower Si with respect surface. However, degree selectivity dependent material. highly selective depositions hydrogen terminated silicon having rates up 180 times than those Si, while similar HfO2 Al2O3...
Spin states in semiconductors provide exceptionally stable and noise-resistant environments for qubits, positioning them as optimal candidates reliable quantum computing technologies. The proposal to use nuclear electronic spins of donor atoms silicon, introduced by Kane 1998, sparked a new research field focused on the precise individual impurity devices, utilising scanning tunnelling microscopy ion implantation. This roadmap article reviews advancements 25 years since Kane's proposal,...
Abstract Spin states in semiconductors provide exceptionally stable and noise-resistant environments for qubits, positioning them as optimal candidates reliable quantum computing technologies. The proposal to use nuclear electronic spins of donor atoms silicon, introduced by Kane 1998, sparked a new research field focused on the precise individual impurity devices, utilising scanning tunnelling microscopy ion implantation. This roadmap article reviews advancements 25 years since Kane’s...
We investigate the different transport mechanisms that can occur in pn junction devices made using atomic precision advanced manufacturing at temperatures ranging from cryogenic to room temperature. first elucidate potential cause of anomalous behavior observed forward-bias response these recent temperature measurements, which deviates theoretical a silicon Esaki diode. These behaviors include current suppression low voltages and much lower valley voltage than theoretically expected for To...
The growth of Ge three-dimensional coherent clusters on Si(001) during gas source molecular-beam epitaxy and post-deposition anneals has been investigated using in situ elevated-temperature scanning tunneling microscopy. By monitoring the individual so-called ``hut'' clusters, this technique allowed us to separate various factors that may affect final size distribution entire cluster ensembles. It found course hut grow by nucleation deposited material facets; however, low rate...
We have imaged hydrogen on Si(001) at low coverages in a variable-temperature STM from 300 K up to 700 K. Individual atoms were which became mobile around 570 The observed rate of hopping along the dimer rows was consistent with an activation energy 1.68 \ifmmode\pm\else\textpm\fi{} 0.15 eV. Motion across rarely observed, even higher temperatures. diffusion barrier for motion has been calculated using tight-binding and density-functional theory generalized gradient approximation (GGA). is...
In top down nanofabrication research facilities around the world, direct-write high-resolution patterning tool of choice is overwhelmingly electron beam lithography. Remarkably small features can be written in a variety polymeric resists [V. R. Manfrinato et al., Nano Lett. 14, 4406 (2014); V. Manfrinato, A. Stein, L. Zhang, Y. Nam, K. G. Yager, E. Stach, and C. T. Black, 17, 4562 (2017)]. However, this technology, which article authors will refer to as conventional lithography (CEBL),...
A method to enhance the speed of scanning tunneling microscope based hydrogen depassivation lithography is presented. In order maximize patterning while maintaining capability retain atomic precision with respect line edges and feature positions, a multimode technique used where modes are characterized either by large or small spot sizes. For areas atomically precise required, tip sample bias 4–4.5 V used. other areas, such as in center solid pattern, (∼7 nm) linewidth field emission 8...
Abstract A materials synthesis method that we call atomic-precision advanced manufacturing (APAM), which is the only known route to tailor silicon nanoelectronics with full 3D atomic precision, making an impact as a powerful prototyping tool for quantum computing. Quantum computing schemes using ( 31 P) spin qubits are compelling future scale-up owing long dephasing times, one- and two-qubit gates nearing high-fidelity thresholds fault-tolerant error correction, emerging routes via proven Si...
Scanning tunneling microscopy (STM) has been used to investigate the adsorption of benzene on nominally flat Si(100)-(2×1) substrates. STM images show that adsorbs top dimer rows bonding two Si–Si dangling bonds. Bias-dependent imaging indicates highest occupied molecular orbital adsorbed lies approximately 1.2 eV below valence band and lowest unoccupied is at least 3.5 above orbital. At higher coverages, molecules are every other along row across resulting in a local c(4×2) periodicity,...
There is an exciting opportunity to start a second digital revolution that will supersede the first in information technology (IT) as primary driver of scientific, technological, and economic growth. This new be fabrication technology. The IT has been largely driven by algorithms such error detection correction Moore's Law which given us exponential trend product capabilities. However, longstanding improving manufacturing precision enabled simply cannot continued much longer because we are...
Ammonia adsorbs dissociatively on the Si(001) surface above $200\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The majority dissociation products are -H and -$\mathrm{N}{\mathrm{H}}_{2}$ groups, adsorbed dangling bonds of Si dimers. At low coverages, ammonia fragments observed to form clumps, which extend both along across dimer rows, suggesting interactions between molecules: either direct interactions, or those mediated by buckled dimers substrate. detailed reactions in adsorption...
A common cause of tip-sample crashes in a Scanning Tunneling Microscope (STM) operating constant current mode is the poor performance its feedback control system. We show that there direct link between Local Barrier Height (LBH) and robustness loop. method known as “gap modulation method” was proposed early STM studies for estimating LBH. obtained measurements are affected by controller parameters propose an alternative which we prove to produce LBH independent dynamics. use estimation...