29 research outputs found
Inelastic Neutron Scattering Studies of \u3csup\u3e132,134\u3c/sup\u3eXe: Elucidating Structure in a Transitional Region and Possible Interferences for 0vββ Searches
Highly enriched (\u3e 99.9%) 132Xe and 134Xe gases were converted to solid 132XeF2 and 134XeF2 and were used as scattering samples for inelastic neutron scattering measurements at the University of Kentucky Accelerator Laboratory (UKAL). Lifetimes of levels up to 3.5MeV in excitation energy in these xenon isotopes were measured using the Doppler-shift attenuation method, allowing the determination of reduced transition probabilities. Gamma rays corresponding to new transitions and levels have been observed. In particular, tentative new excited 0+ states and associated decays have been examined in an effort to elucidate the structure of these nuclei in a transitional region, and comparisons have been drawn with models which seek to describe such nuclei, e.g., the E(5) critical-point symmetry of the IBM. Newly identified potential interferences for neutrinoless double-beta decay searches involving 136Xe are also discussed
0\u3csup\u3e+\u3c/sup\u3e States in \u3csup\u3e130,132\u3c/sup\u3eXe: A Search for E(5) Behavior
The level structures of 130,132Xe were studied with the inelastic neutron scattering reaction followed by Îł-ray detection. Level lifetimes were measured using the Doppler-shift attenuation method and low-lying excited states in these nuclei were characterized. With a focus on the decay properties of the 0+ states, these nuclei were examined as representations of the E(5) critical-point symmetry
In-Situ Probe of Gate Dielectric-Semiconductor Interfacial Order in Organic Transistors: Origin and Control of Large Performance Sensitivities
Organic thin film transistor (OTFT) performance is highly
materials
interface-dependent, and dramatic performance enhancements can be
achieved by properly modifying the semiconductor/gate dielectric interface.
However, the origin of these effects is not well understood, as this
is a classic “buried interface” problem that has traditionally
been difficult to address. Here we address the question of how <i>n</i>-octadecylsilane (OTS)–derived self-assembled monolayers
(SAMs) on Si/SiO<sub>2</sub> gate dielectrics affect the OTFT performance
of the archetypical small-molecule p-type semiconductors P-BTDT (phenylbenzoÂ[<i>d</i>,<i>d</i>]ÂthienoÂ[3,2-<i>b</i>;4,5-<i>b</i>]Âdithiophene) and pentacene using combined in situ sum
frequency generation spectroscopy, atomic force microscopy, and grazing
incidence and reflectance X-ray scattering. The molecular order and
orientation of the OTFT components at the dielectric/semiconductor
interface is probed as a function of SAM growth mode in order to understand
how this impacts the overlying semiconductor growth mode, packing,
crystallinity, and carrier mobility, and hence, transistor performance.
This understanding, using a new, humidity-specific growth procedure,
leads to a reproducible, scalable process for highly ordered OTS SAMs,
which in turn nucleates highly ordered p-type semiconductor film growth,
and optimizes OTFT performance. Surprisingly, the combined data reveal
that while SAM molecular order dramatically impacts semiconductor
crystalline domain size and carrier mobility, <i>it does not
significantly influence the local orientation of the overlying organic
semiconductor molecules</i>