Pentacene stands out as a model molecule among organic semiconductors due to its ability form well-ordered films that show high field effect mobility. We discuss the processes involved in pentacene film growth, emphasizing differences with respect inorganic films. The influence of growth parameters such substrate nature and temperature, deposition rate, kinetic energy molecular beam on structure morphology are discussed. Finally, we overview recent attempts nucleation draw attention role...

Grazing incidence x-ray scattering was used to determine the temperature and ion-energy dependence of nanoscale corrugations that form on an amorphous SiO2 surface eroded by Ar+ ions. The corrugation wavelength lambda* shows a nearly linear ion energy. Between room approximately 200 degrees C, depends weakly above C it Arrhenius-like increase. Ion-assisted viscous relaxation in thin layer is shown be dominant smoothing process during erosion; rate scales as (lambda*)(-4).

Synchrotron x-ray diffraction has been used to analyze the (\ensuremath{\surd}3\ifmmode\times\else\texttimes\fi{}\ensuremath{\surd}3)R30\ifmmode^\circ\else\textdegree\fi{} reconstruction of B/Si(111). Excellent agreement is obtained with in-plane data for a model in which boron sits every third site threefold symmetry. Out-of-plane diffraction, however, only consistent below surface fivefold-coordinated substitutional under silicon ${\mathrm{T}}_{4}$ adatom. The structure confirmed by growth...

Grazing incidence x-ray diffraction, reflectivity and atomic force microscopy have been performed to study the structure of pentacene thin films on oxidized Si substrates from submonolayer multilayer coverages. The volume unit cell in film phase is almost identical that bulk phase, thus molecular packing efficiency effectively same both phases. forming first monolayer remains for at least 190Å thick. in-plane islands also unchanged within a substrate temperature range...

The hollow pen method for writing thin films of materials from solution is utilized to deposit 6,13-bis(tri-isopropylsilylethynyl) pentacene (TIPS pentacene) onto SiO2 surfaces with pre-patterned source/drain gold contacts. We demonstrate that large domains are obtained TIPS deposited 0.5–4.0wt% solutions toluene. Crystalline grains (001) orientation observed grow sizes can exceed 1mm along the direction. A preferred azimuthal also selected by process, resulting in anisotropic field effect...

The formation of self-organized Si nanostructures induced by Mo seeding during normal incidence Ar+ ion bombardment at room temperature is reported. Silicon surfaces without develop only power-law roughness 1000eV incidence, in agreement with scaling theory expectations surface roughening. However, supplying atoms to the seeds development highly correlated, nanoscale structures (“dots”) that are typically 3nm high a spatial wavelength approximately 30nm. With time, these saturate and further...

We have investigated the effect of surface order on orientation and mobility pentacene. The was created using monolayers polymers that are normally used to align liquid crystals. Rubbed polyvinylalcohol layers were found approximately 27% pentacene grains within a 30° range. When introduced in thin-film transistor, they enhance saturation current by factor 2.5. A mechanism for this enhancement is proposed.

X-ray scattering data at high instrumental resolution are reported for multilamellar vesicles of La phase lipid bilayers 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine 500C under varying osmotic pressure.The fitted to two theories that account noncrystalline disorder, paracrystalline theory (PT) and modified Caille (MCT).The MCT provides good fits the data, much better than PT fits.The particularly important characteristic is long power law tails in scattering.PT (as well as ordinary...

Aligned samples of lipid bilayers have been fully hydrated from water vapor in a different type x-ray chamber. Our use aligned resolves issues concerning the ripple phase that were ambiguous previous powder studies. In particular, our diffraction data conclusively demonstrate that, on cooling ${L}_{\ensuremath{\alpha}}$ to ${P}_{{\ensuremath{\beta}}^{\ensuremath{'}}}$ phase, both chiral and racemic dipalmitoyl phosphatidylcholine (DPPC) exhibit coexistence long short ripples with wavelength...

Using real-time x-ray scattering to measure the surface morphology of Au(111) during sputter erosion with 500 eV ${\mathrm{Ar}}^{+}$ ions, we observe three distinct regimes: three-dimensional rough at 20-- $60\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$, quasi-layer-by-layer removal 120-- $220\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$, and step retraction above $270\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$. Sputtering $60\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ leads pattern...

We have produced solution-processed thin films of 6,13-bis(triisopropyl-silylethynyl) pentacene with grain sizes from a few micrometers up to millimeter scale by lateral crystallization rectangular stylus. Grains are oriented along the direction, and size transverse direction depends inversely on writing speed, hence forming regular array boundaries controllable spacing. utilize these arrays systematically study role large-angle in carrier transport charge trapping film transistors. The...

Effects of seed atoms on the formation nanodots silicon surfaces during normal incidence Ar+ ion bombardment at room temperature are studied with real-time grazing-incidence small-angle x-ray scattering (GISAXS), wafer curvature stress measurements and ex situ atomic force microscopy. Although Si remain smooth temperature, when a small amount Mo is supplied to surface bombardment, development correlated structures (“dots”) observed. Stress show that initially compressive develops likely due...

High resolution x-ray scattering measurements on model membranes consisting of fully hydrated lipid bilayers have been performed to evaluate the origin anomalous temperature dependence lamellar $D$ spacing. The data are well fit by our recent refinement theory power law tails that occur in fluctuating smectic liquid crystals. show increase is due an thickness bilayer, caused critical straightening hydrocarbon chains, and little change undulation force takes place.

Traditional techniques for growing Si-Ge layers have centered around low-temperature growth methods such as molecular-beam epitaxy and ultrahigh vacuum chemical vapor deposition in order to achieve strain metastability good control. Recognizing that metastable films are probably undesirable state-of-the-art devices on the basis of reliability considerations, general, crystal perfection increases with increasing temperatures, we grown mechanically stable (i.e., whose composition thickness...

Single-crystal silicon films grown at 400 \ifmmode^\circ\else\textdegree\fi{}C on Si(111):B(\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 ) are rotated 180\ifmmode^\circ\else\textdegree\fi{} about the surface normal with respect to substrate. We discuss a mechanism based chemical effects due boron (\ensuremath{\surd}3 reconstruction that favors film grow B-type (twin) orientation. Films Si(111)-(7\ifmmode\times\else\texttimes\fi{}7) under identical conditions...

Real-time synchrotron x-ray scattering in the anti-Bragg configuration was used to monitor dynamics of pentacene film growth on inert substrates. A distributed-growth model, according which molecules adsorbed $n\text{th}$ layer can either nucleate and contribute $(n+1)\text{th}$ or transfer downward layer, gave a good description data. For first second layers, probability found be dependent substrate, independent temperature within range from...

Abstract In epitaxially strained ferroelectric thin films and superlattices, the transition temperature can lie above growth temperature. Ferroelectric polarization domains should then evolve during of a sample, electrostatic boundary conditions may play an important role. this work, domains, surface termination, average lattice parameter bilayer thickness are simultaneously monitored using in situ synchrotron X-ray diffraction BaTiO 3 /SrTiO superlattices on SrTiO substrates by off-axis...

We have compared ion channeling results with molecular dynamics simulations to investigate low-temperature beam homoepitaxy on silicon. report the temperature dependence, rate and thickness dependence of films grown Si(111). For 350 Å films, a transition good crystalline quality is seen in at growth temperatures ≊400 °C; this ≊100 °C for (100) epitaxy. The evolution surface microstructure leading breakdown epitaxial low discussed.

A (2×1) surface reconstruction distinct from the clean Si(100)-(2×1) is formed by depositing boron onto silicon in ultrahigh vacuum. Overgrowth of epitaxial at low temperature preserves a superstructure substitutional boron. Hall-effect measurements 4.2 K show complete electrical activity for coverages 1/2 monolayer, but additional above monolayer not electrically active.

Grazing incidence small-angle x-ray scattering and atomic force microscopy have been used to systematically investigate the evolution of Si(100) surface morphology during normal-incidence Ar+ sputtering as a function ion energy in range 100–500 eV. For ranges 100–300 eV, two structures with distinct individual length scales behaviors form on surface. There is smaller scale (lateral size 20–50 nm) that grows intensity coarsens time. also larger approximately 100 but does not coarsen...

We have undertaken a new set of experiments to investigate the behavior adsorbed-impurity induced reconstructions at growth interfaces. observed striking difference in stability B(3)1/2×(3)1/2 and Ga(3)1/2×(3)1/2 two-dimensional structures interface between Si(111) a-Si, their segregation during molecular beam epitaxy crystal growth. This leads model dopant silicon epitaxy.

A study of ripple formation on sapphire surfaces by $300--2000\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ ${\mathrm{Ar}}^{+}$ ion bombardment is presented. Surface characterization in-situ synchrotron grazing incidence small angle x-ray scattering and ex-situ atomic force microscopy performed in order to the wavelength ripples formed (0001) surfaces. We find that can be varied over a remarkably wide range---nearly two orders magnitude---by changing angle. Within linear theory regime, induced...

At least two different routes lead to conical structures on laser ablated polymer surfaces. These were investigated by studying ablation the surfaces of classes polymers. Cones appeared readily in strongly absorbing polymers such as poly(ethylene terephthalate) (PET) and polyimide (PI), but only within narrow parameters nylon 6, rarely poly(chlorotrifluoroethylene), last being weak ultraviolet (UV) absorbers. Self-assembled, close-packed cones occurred PET, which heat generated due absorbed...