Enhanced Solar Reflectance and Superhydrophobic Properties of Functionalized Silica-Coated Copper Phthalocyanine Pigments by the Sol-Gel Process.

This research studies the physical, superhydrophobic, and optical properties of functionalized silica-coated copper phthalocyanine (CuPc) pigments. The silica coating was confirmed by the size increase and the atomic ratio of silicon and copper of the coated pigments. Under optimal conditions, the green and blue shades of the pigments were enhanced as indicated by the increase in solar reflectance at 450-540 nm for the CuPc green and 380-520 nm for the CuPc blue. The total near-infrared (NIR) reflectance of the CuPc green and blue also increases by 10.6 and 11.5% compared to the uncoated pigments, respectively. The functionalized silica layer also adds a superhydrophobic property to the pigments. The contact angles of the functionalized pigments with water and oil are 154.4 and 54.3° for the CuPc green pigment and 142.9 and 78.1° for the CuPc blue pigment, respectively. The improved optical and hydrophobic properties make the pigment suitable for outdoor applications as an advanced protection layer to slow down material degradations from heat and humidity.

The influence of surface preparation on low temperature HfO2 ALD on InGaAs (001) and (110) surfaces.

Current logic devices rely on 3D architectures, such as the tri-gate field effect transistor (finFET), which utilize the (001) and (110) crystal faces simultaneously thus requiring passivation methods for the (110) face in order to ensure a pristine 3D surface prior to further processing. Scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy (XPS), and correlated electrical measurement on MOSCAPs were utilized to compare the effects of a previously developed in situ pre-atomic layer deposition (ALD) surface clean on the InGaAs (001) and (110) surfaces. Ex situ wet cleans are very effective on the (001) surface but not the (110) surface. Capacitance voltage indicated the (001) surface with no buffered oxide etch had a higher C(max) hypothesized to be a result of poor nucleation of HfO2 on the native oxide. An in situ pre-ALD surface clean employing both atomic H and trimethylaluminum (TMA) pre-pulsing, developed by Chobpattana et al. and Carter et al. for the (001) surface, was demonstrated to be effective on the (110) surface for producing low D(it) high C(ox) MOSCAPs. Including TMA in the pre-ALD surface clean resulted in reduction of the magnitude of the interface state capacitance. The XPS studies show the role of atomic H pre-pulsing is to remove both carbon and oxygen while STM shows the role of TMA pre-pulsing is to eliminate H induced etching. Devices fabricated at 120 °C and 300 °C were compared.

The formation and utility of sub-angstrom to nanometer-sized electron probes in the aberration-corrected transmission electron microscope at the University of Illinois.

We evaluate the probe forming capability of a JEOL 2200FS transmission electron microscope equipped with a spherical aberration (Cs) probe corrector. The achievement of a real space sub-Angstrom (0.1 nm) probe for scanning transmission electron microscopy (STEM) imaging is demonstrated by acquisition and modeling of high-angle annular dark-field STEM images. We show that by optimizing the illumination system, large probe currents and large collection angles for electron energy loss spectroscopy (EELS) can be combined to yield EELS fine structure data spatially resolved to the atomic scale. We demonstrate the probe forming flexibility provided by the additional lenses in the probe corrector in several ways, including the formation of nanometer-sized parallel beams for nanoarea electron diffraction, and the formation of focused probes for convergent beam electron diffraction with a range of convergence angles. The different probes that can be formed using the probe corrected STEM opens up new applications for electron microscopy and diffraction.