444 research outputs found
Detection of low energy single ion impacts in micron scale transistors at room temperature
We report the detection of single ion impacts through monitoring of changes
in the source-drain currents of field effect transistors (FET) at room
temperature. Implant apertures are formed in the interlayer dielectrics and
gate electrodes of planar, micro-scale FETs by electron beam assisted etching.
FET currents increase due to the generation of positively charged defects in
gate oxides when ions (121Sb12+, 14+, Xe6+; 50 to 70 keV) impinge into channel
regions. Implant damage is repaired by rapid thermal annealing, enabling
iterative cycles of device doping and electrical characterization for
development of single atom devices and studies of dopant fluctuation effects
Method and means for odor control in waste water lagoons
A method for controlling odor in a waste water lagoon comprises the steps of aerating a top horizontal layer of a lagoon adjacent its upper surface at a depth of approximately 12 to 24 inches by introducing air through a plurality of nozzles submerged in the layer to create a plurality of air bubbles in the layer. The nozzles are moved horizontally through the layer. A device for controlling the odor in waste water lagoons includes a support structure with an elongated boom operatively secured to the support structure and extending outwardly therefrom to operatively contact water in an adjacent lagoon. Compressed air is delivered through a plurality of downwardly extending nozzles on the boom into a layer of water on the top of the lagoon approximately 12 to 24 inches deep. Power elements are secured to the boom to cause the boom to move horizontally with respect to the lagoon while the compressed air is being delivered through the nozzles
Processing Issues in Top-Down Approaches to Quantum Computer Development in Silicon
We describe critical processing issues in our development of single atom
devices for solid-state quantum information processing. Integration of single
31P atoms with control gates and single electron transistor (SET) readout
structures is addressed in a silicon-based approach. Results on electrical
activation of low energy (15 keV) P implants in silicon show a strong dose
effect on the electrical activation fractions. We identify dopant segregation
to the SiO2/Si interface during rapid thermal annealing as a dopant loss
channel and discuss measures of minimizing it. Silicon nanowire SET pairs with
nanowire width of 10 to 20 nm are formed by electron beam lithography in SOI.
We present first results from Coulomb blockade experiments and discuss issues
of control gate integration for sub-40nm gate pitch levels
Chemical Raman Enhancement of Organic Adsorbates on Metal Surfaces
Using a combination of first-principles theory and experiments, we provide a
quantitative explanation for chemical contributions to surface-enhanced Raman
spectroscopy for a well-studied organic molecule, benzene thiol, chemisorbed on
planar Au(111) surfaces. With density functional theory calculations of the
static Raman tensor, we demonstrate and quantify a strong mode-dependent
modification of benzene thiol Raman spectra by Au substrates. Raman active
modes with the largest enhancements result from stronger contributions from Au
to their electron-vibron coupling, as quantified through a deformation
potential, a well-defined property of each vibrational mode. A straightforward
and general analysis is introduced that allows extraction of chemical
enhancement from experiments for specific vibrational modes; measured values
are in excellent agreement with our calculations.Comment: 5 pages, 4 figures and Supplementary material included as ancillary
fil
Electrical activation and electron spin coherence of ultra low dose antimony implants in silicon
We implanted ultra low doses (2x10^11 cm-2) of 121Sb ions into isotopically
enriched 28Si and find high degrees of electrical activation and low levels of
dopant diffusion after rapid thermal annealing. Pulsed Electron Spin Resonance
shows that spin echo decay is sensitive to the dopant depths, and the interface
quality. At 5.2 K, a spin decoherence time, T2, of 0.3 ms is found for profiles
peaking 50 nm below a Si/SiO2 interface, increasing to 0.75 ms when the surface
is passivated with hydrogen. These measurements provide benchmark data for the
development of devices in which quantum information is encoded in donor
electron spins
Spin-Dependent Scattering off Neutral Antimony Donors in 28-Si Field-Effect Transistors
We report measurements of spin-dependent scattering of conduction electrons
by neutral donors in an accumulation-mode field-effect transistor formed in
isotopically enriched silicon. Spin-dependent scattering was detected using
electrically detected magnetic resonance where the spectra show resonant
changes in the source-drain voltage for conduction electrons and electrons
bound to donors. We discuss the utilization of spin-dependent scattering as a
mechanism for the readout of donor spin-states in silicon based quantum
computers.Comment: 14 pages, 3 figures. Correction made to figure3(b
- …