The nucleation mechanisms during solution deposition of organic semiconductor thin films determine the grain morphology and may influence the crystalline packing in some cases. Here, in-situ optical spectromicroscopy in reflection mode is used to study the growth mechanisms and thermal stability of 6,13-bis(trisopropylsilylethynyl)-pentacene thin films. The results show that the films form in a supersaturated state before transforming to a solid film. Molecular aggregates corresponding to subcritical nuclei in the crystallization process are inferred from optical spectroscopy measurements of the supersaturated region. Strain-free solid films exhibit a temperature-dependent blue shift of optical absorption peaks due to a continuous thermally driven change of the crystalline packing. As crystalline films are cooled to ambient temperature they become strained although cracking of thicker films is observed, which allows the strain to partially relax. Below a critical thickness, cracking is not observed and grazing incidence X-ray diffraction measurements confirm that the thinnest films are constrained to the lattice constants corresponding to the temperature at which they were deposited. Optical spectroscopy results show that the transition temperature between Form I (room temperature phase) and Form II (high temperature phase) depends on the film thickness, and that Form I can also be strain-stabilized up to 135 °C.

An apparatus, capable of measuring the dc resistance versus temperature of a 49-member library prepared by thin-film deposition techniques was designed and tested. The library is deposited by dc magnetron sputtering onto 10.16 cmϫ 10.16 cm alumina substrates on which are placed aluminum masks consisting of 8 mm diam holes cut on a 7 ϫ 7 grid, the center-to-center spacing being 10.15 mm. Electrical contact to the library is made in a standard van der Pauw geometry using 196 spring-loaded, gold-coated pins, four pins for each member of the library. The temperature is controlled using a helium refrigerator in combination with a liquid-nitrogen radiation shield that greatly reduces radiative heating of the sample stage. With the radiation shield, the cold finger is able to sustain a minimum temperature of 7 K and the sample stage a minimum temperature of 27 K. The temperature ͑27-291 K͒ dependent dc resistivity of a thin-film silver library of varying thickness ͑48-639 nm͒ is presented to highlight the capabilities of the apparatus. The thickness dependence of both the resistivity and the temperature coefficient of resistivity are quantitatively consistent with the literature. For thicknesses greater than about 100 nm, the room-temperature resistivity ͑3.4 ⍀ cm͒ are consistent with Matthiessen's rule for 1%-2% impurity content, and the temperature coefficient of resistivity is consistent with the bulk value. For thicknesses less than 100 nm, an increase in resistivity by a factor of 8 is found, which may be due to surface and boundary scattering effects; a corresponding increase in the temperature coefficient of resistivity is consistent with a concomitant decrease in the magnitude of the elastic constants and surface scattering effects.

a b s t r a c tThe electrical and optical properties of InZnO for use as a transparent conducting oxide (TCO) is reported through the investigation of the concentration of indium and oxygen in the film. InZnO films (10-30 wt.% In) were deposited by magnetron sputtering without substrate heating or annealing from a ceramic ZnO and a metallic indium target. The film's properties were investigated by X-ray photoelectric spectroscopy (XPS), 4-point probe, UV-vis spectroscopy (UV-vis), spectroscopic ellipsometry, and Hall measurements. InZnO films obtained properties with low resistivity, on the order of $5.5 Â 10 À4 ohm-cm, with a mobility $35 cm 2 /V S, and carrier concentrations $3 ⁄ 10 20 cm À3 . The band-gap ranged from 2.7 to 3.2 eV with transmission of several samples >80%. InZnO has demonstrated properties adequate for photovoltaic applications.

Noble metal nanoparticles exhibit significant potential in all-optical, smart-sensing applications due to their unique optical properties. In particular, gold (Au) nanoparticles exhibit a strong surface plasmon resonance (SPR) band, the spectral position and shape of which depends on the size, shape, and density of the nanoparticles and the physical and chemical properties of surrounding environment. Embedding the nanoparticles in an yttria-stabilized zirconia (YSZ) matrix is believed to expand their range of operation to temperatures above 500 °C. YSZ is a material that has been proven suitable for optical applications due to its high refractive index, low absorption coefficient and high transparency in the visible and infrared regions. Thus, its use as a base platform for nanocomposite thin films is expected to provide significant benefits in the development of harsh environment multifunctional sensors.In this work YSZ-Au nanocomposite films were synthesized from a YSZ and a Au target by the radio frequency magnetron co-sputtering technique in combination with a post-deposition annealing treatment in an argon atmosphere, with the annealing temperature being varied from 500-1000 °C in steps of 100 °C. The microstructure and the optical properties of the resulting films were characterized by x-ray diffraction spectroscopy, scanning electron microscopy and spectroscopic ellipsometry. Results on the effect of the Au particle size on the real and the imaginary part of the refractive index of the nanostructured composites are presented. Future smart sensor systems utilizing these multifunctional material sets for harsh environment sensing applications will likewise be outlined.

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