bluuebunny/crossref_metadata_2025_split huggingface dataset:
N- and P-Type Building Blocks for Organic Electronics Based on Oligothiophene Cores
Authors: Facchetti Antonio , Yoon Myung-Han , Katz Howard E. , Mushrush Melissa , Marks Tobin J. 
Published: June 2019

AbstractOrganic semiconductors exhibiting complementary-type carrier mobility are the key components for the development of the field of “plastic electronics”. We present here a novel series of αω- and isomerically pure β,β'-diperfluorohexyl-substituted thiophene and study the impact of fluoroalkyl substitution and conjugation length vìs-à-vìs the corresponding fluorinefree analogues. Trends between the fluorinated and fluorine-free families in molecular packing, HOMO-LUMO gap, and π-π interactions are found to be strikingly similar. TFT measurements indicate that all members of the fluorinated series are n-type semiconductors
Thin Film Transistors on Plastic Substrates Using Silicon Deposited by Microwave ECR-CVD
Authors: Teng Lihong , Anderson Wayne A. 
Published: June 2019

AbstractThe properties of thin film transistors (TFT's) on plastic substrates with active silicon films deposited by microwave ECR-CVD were studied. Two types of plastic were used, PEEK and polyimide. The a-Si:H TFT deposited at 200°C on polyimide substrates showed a saturation field effect mobility of 4.5 cm2/V-s, a threshold voltage of 3.7 V, a subthreshold swing of 0.69 V/dec and an ON/OFF current ratio of 7.9×106, while the TFT fabricated on PEEK at 200°C showed a saturation field effect mobility of 3.9 cm2/V-s, a threshold voltage of 4.1 V, a subthreshold swing of 0.73 V/dec and an ON/OFF current ratio of 4×106. Comparison is made to TFT's with the Si deposited at 400°C on glass.
High Performance Plastic Transistors With Printed Polyaniline Electrodes
Authors: Lefenfeld Michael , Blanchet Graciela , Rogers John A. 
Published: June 2019

AbstractThis article describes the properties of transistors that use organic semiconductors deposited on top of conducting polymer electrodes patterned by thermal transfer printing onto thin plastic sheets. The polymer, dinonylnaphthalene sulfonic acid doped polyaniline (DNNSA-PANI), contains several weight percent of single walled carbon nanotubes (SWNT) to improve its conductivity. Pentacene serves as the p-type organic semiconductor. The good electrical performance of these devices derives directly from the low resistance contacts between the printed DNNSA-PANI/SWNT source/drain electrodes and the pentacene. The measurements presented here quantify the behavior of these contacts and provide some morphological evidence for their low resistance. The excellent characteristics of the transistors and the operational flexibility of the thermal transfer printing technique that is used to pattern them represent results that may be an important step for the development of means to build realistic flexible electronic devices.
Flexible organic field-effect transistors fabricated by the electrode-peeling transfer
Authors: Yasuda Takeshi , Fujita Katsuhiko , Tsutsui Tetsuo 
Published: June 2019

AbstractWe report a simple and mild fabrication of flexible organic field-effect transistors (OFETs) by an electrode-peeling transfer method. Firstly, fine patterns of source-drain metal electrodes were formed on a solid substrate, where a micro-patterning process such as photolithography is applicable. An organic dielectric layer (poly-chloro-p-xylylene) was deposited by a chemical vapor deposition. Then patterned gate electrode was deposited using a shadow mask. On the top surface of the gate electrode, another adhesive flexible substrate was fixed and the stack of the flexible substrate/gate electrode /dielectric layer /source-drain electrode was peeled away from the solid substrate. The peeling-transfer was completed with a help of a self-assembled monolayer of n-decyl mercaptan as a connecting buffer layer between the gold electrodes and the dielectric layer. Then an organic semiconductor material was deposited on the fresh peeled-off surface on the flexible substrate. When pentacene was used as the semiconductor material, the OFETs exhibited a hole mobility of 0.1 cm2/Vs and a current on/off ratio of 105.
Low Temperature Copper-induced Crystallization Technique for Germanium on Flexible PET, by Means of Mechanical Compressive Stress
Authors: Hekmatshoar B. , Shahrjerdi D. , Mohajerzadeh S. , Khakifirooz A. , Akhavan A. , Robertson M. 
Published: June 2019

AbstractLow temperature copper-induced crystallization of amorphous germanium (a-Ge) has been significantly enhanced by applying mechanical compressive stress during thermal post-treatment. Manipulation of this technique, alongside with proper patterning of the a-Ge layer before thermo-mechanical process, has led to growth of device-quality poly-Ge layer on flexible PET substrate at temperatures as low as 130°C. Flexibility of the substrate allows the efficient application of uniaxial compressive stress by bending the PET sheets inward. Effects of compressive stress and ultimate crystallization of the Ge layer has been verified by electrical sheet resistance and Hall mobility measurements, and analyzed by XRD, SEM, TEM and RAMAN spectroscopy.
A Method for Making Elastic Metal Interconnects
Authors: Jones Joyelle , Lacour Stéphanie Périchon , Wagner Sigurd , Suo Zhigang 
Published: June 2019

AbstractStretchable, elastic metal interconnects are a key to the fabrication of 3-D conformal circuits and electrotextiles. The basic concept for reversibly stretchable, elastic metallization is a corrugated stripe of thin-film metal that is expanded by stretching. The maximum elongation is reached when the stripe is stretched flat. We prepared wavy metal stripes by evaporating gold onto pre-stretched strips of the elastomer, poly-dimethyl siloxane (PDMS). We experimented with gold metal line width and thickness and substrate elongation. We measured the film structure, amplitude, and wavelength, as well as electrical resistance in relaxed and various stretched states. So far we have reached elastic strains of 15% while maintaining the initial resistance and 80% with a rise in the resistance. We discovered a rich macroscopic and microscopic film morphology. Presented are the fabrication, electro-mechanical performance, and data on the film structure of these wavy metal interconnects.
Light trapping in amorphous silicon solar cells on plastic substrates
Authors: Terrazzoni-Daudrix Vanessa , Guillet Joelle , Niquille Xavier , Shah Arvind , Morf R. , Tishchenko A. , Brioude V. , Parriaux O. , Fischer D. 
Published: June 2019

AbstractIn order to simultaneously decrease the production costs of thin film silicon solar cells and obtain higher performances, the authors have studied the possibility to increase the light trapping effect within thin film silicon solar cells deposited on flexible plastic substrates. In this context, different nano-structure shapes useable for the back contacts of amorphous silicon solar cells on plastic substrates have been investigated: random textures and gratings.The optimisation of such back reflectors is so far empirical. Gratings constitute a well-known optical technique and their light trapping effect can be optimised by simulation.A first conclusion is that neither the traditional “Haze factor” determined in air for a wavelength of 650nm nor the “rms roughness” of the surfaces are sufficient as criteria to optimise the back contact roughness for light trapping in cells. The shape of grains is a further essential criterion. The authors have so far obtained a relative current enhancement of 16% for solar cells deposited on randomly textured polyethylene terephthalate (PET) as compared to a corresponding conventional solar cell co-deposited on a flat mirror (Ag) on glass. Solar cells on PET with 6.3% stabilized efficiency have until now been obtained. Theoretical calculations indicate that gratings can enhance the current of a-Si solar cells by up to 30 percent.
Molecular Dynamics Simulation of Germanium Nanoparticles
Authors: Yang Sang H. , Berry Rajiv J. 
Published: June 2019

AbstractNanoparticles are known to melt at temperatures well below the bulk melting point. This behavior is being exploited for the recrystallization of Germanium to form large-grain semiconductor thin films on flexible and low temperature substrates. The melting of Ge nanoparticles as a function of size was investigated using the ab-initio Harris functional method of density functional theory (DFT).The DFT code was initially evaluated for its ability to predict the bulk properties of crystalline Ge. A conjugate gradient method was employed for minimizing the multiphase atomic positional parameters of the diamond, BC8 and ST12 structures. The computed lattice constants, bulk moduli, and internal atomic positional parameters were found to agree well with other calculations and with reported experimental results.A constant temperature Nose-Hoover thermostat was added to the DFT code in order to compute thermal properties via molecular dynamics. The simulations were tested on a 13-atom Ge cluster, which was found to melt at 820 K. Further heating resulted in the cluster breaking up into two smaller clusters, which remained stable up to 1300K.
The Characteristics of Silicon Dioxide Deposited by Inductively Coupled Plasma Chemical Vapor Deposition at 150°C
Authors: Kang Su-hyuk , Lee Min-Cheol , Moon Kook-Chul , Han Min-koo 
Published: June 2019

AbstractAn ultra-low temperature processed silicon dioxide film has been fabricated by inductively coupled plasma chemical vapor deposition at 150°C using He/N2O/SiH4 mixture. The deposited silicon dioxide film exhibits a high breakdown field larger than 6MV/cm in case of high ICP plasma condition while the flat band voltage of the oxide film significantly shifted in the negative direction with increasing ICP power. In order to obtain both high electrical breakdown filed and the low flat-band voltage, excimer laser irradiation with the energy density of 430mJ/cm2 is employed. The oxide film irradiated by excimer laser exhibited considerably shifted in the positive direction without scarifying the breakdown characteristics.
Thin Film Morphology and GrowthMechanism of Pentacene Thin Film Using Low-Pressure Organic Vapor Deposition
Authors: Ahn Seong Deok , Kang Seung Youl , Lee Yong Eui , Joung Meyoung Ju , Kim Chul Am , Suh Kyung Soo 
Published: June 2019

AbstractWe have investigated the growth mechanism and thin film morphology of pentacene thin films by the process of low-pressure gas assisted organic vapor deposition (LP-GAOVD). As the source temperature, flow rate of the carrier gas, substrate temperature and chamber pressure were varied, the growth rate, morphology and grain size of the films were differently obtained. The electrical properties of pentacene thin films for applications in organic thin film transistor and electrophoretic displays were discussed
The Electronic Circuit Composition and Structure of Warp and Woof for a Novel Hybrid Opto-Electronic Integrated Systems with Textile Structures
Authors: Kuniyoshi Shigekazu , Tanaka Kuniaki 
Published: June 2019

AbstractThe new integrated circuit concept that forms electronic equipment by the textile structure using the flexible fiber that has equipped the field effect transistor, the light emitting diode, the wiring pattern, etc. is proposed [1]. In this report, the structure of the filamentous body as a basic structure of the cloth with various electronic functions was examined. In order to simplify circuit composition, an active element such as field effect transistors, the electrode pattern for wiring, and the pads for connection are formed on the warp, and the electrode pattern for wiring and the pad for connection are formed on the woof. The circuit composition and a concrete structure of the warp and the woof are discussed.
Inorganic-organic hybrid materials for polymer electronic applications
Authors: Houbertz R. , Schulz J. , Fröhlich L. , Domann G. , Popall M. 
Published: June 2019

AbstractFor applications in polymer electronics, suitable passivation coatings are searched for. Inorganic-organic hybrid polymers (ORMOCER®.s) have proven to be tunable in a wide range with respect to their physical properties. Their synthesis can be controlled such that the resulting materials show very low water vapor transition rates (WVTR) which is one of the most important key properties for passivation applications. Besides, ORMOCER®.s can be patterned by UV lithography due to their organic functional groups thus yielding the possibility of selectively passivate electronic circuits. Typical WVTR values which have been achieved so far for individual thin-film layers range between approximately 1 and 5 g/m2d (calculated for 100 μm layer thickness). The passivation properties will be discussed with respect to variations of the inorganic content and to the network formed upon processing.
Effect of Microcavity Structures on the Photoluminescence of Silicon Nanocrystals
Authors: Spooner Marc G. , Walsh Timothy M. , Elliman Robert G. 
Published: June 2019

Abstractptical microcavity structures containing Si nanocrystals are fabricated by plasma enhanced chemical vapour deposition (PECVD) of SiO2, Si3N4 and SiOx layers. The nanocrystals are formed within Si-rich oxide layers (SiOx) by precipitation and growth, and the microcavity structures defined by two parallel distributed Bragg mirrors (DBM) made from either alternate SiO2/Si3N4 layers or alternate SiO2/SiOx layers. In the latter case, Si nanocrystal layers form part of the DBM structure thereby providing a distributed emission source. The optical emission from these and related structures are examined and compared with that from isolated nanocrystal layers.
Electronic and Optical Properties of Silicon Nanocrystals: Structural Effects
Authors: Degoli E. , Ossicini S. , Luppi M. , Luppi E. , Magri R. , Cantele G. , Ninnoc D. 
Published: June 2019

AbstractThe aim of this work is to investigate the structural, electronic and optical properties of hydrogenated Si nanoclusters (H-Si-nc) in their ground and excited state configurations. Structural relaxations have been fully taken into account in all cases through total energy pseudopotential calculations. Recent results about ab-initio calculations of Stokes shift as a function of the cluster dimension and of optical gain will be presented here. A structural model that can be linked to the four level scheme recently invoked to explain the experimental outcomes relative to the observed optical gain in Si-nc embedded in a SiO2 matrix will be suggested too.
High Efficiency Light Emission Devices in Silicon
Authors: Castagna Maria E. , Coffa Salvatore , Monaco Mariantonietta , Muscara' Anna , Caristia Liliana , Lorenti Simona , Messina Alberto 
Published: June 2019

AbstractWe report on the fabrication and performances of the most efficient Si-based light sources. The devices consist of MOS structures with erbium (Er) implanted in the thin gate oxide. The devices exhibit strong 1.54 μm electroluminescence at 300K with a 10% external quantum efficiency, comparable to that of standard light emitting diodes using III-V semiconductors. Emission at different wavelenghts has been achieved incorporating different rare earths (Ce, Tb, Yb, Pr) in the gate dielectric. The external quantum efficiency depends on the rare earth ions incorporated and ranges from 10% (for an Tb doped MOS) to 0.1% (for an Yb doped MOS). RE excitation is caused by hot electrons impact and oxide wearout limits the reliability of the devices. Much more stable light emitting MOS devices have been fabricated using Er-doped SRO (Silicon Rich Oxide) films as gate dielectric. These devices show a high stability, with an external quantum efficiency reduced to 0.2%. In these devices Er pumping occurs part by hot electrons and part by energy transfer from the Si nanostructures to the rare earth ions, depending by Si excess in the film. Si/SiO2 Fabry-Perot microcavities have been fabricated to enhance the external quantum emission along the cavity axis and the spectral purity of emission from the films that are used as active media to realize a Si based RCLED (resonant cavity light emitting diode). These structures are realized by chemical vapour deposition on a silicon substrate. The microcavities are tuned at different wavelengths: 540nm, 980nm and 1540nm (characteristic emission wavelengths respectively for Tb, Yb and Er). The reflectivity of the microcavities is of 97% and the quality factor ranges from 60 (for the cavity tuned at 980nm) to 95 (for the cavities tuned at 540nm and 1540nm).
Near-infrared Ge Photodetectors Fabricated on Si Substrates with CMOS Technology
Authors: Cannon Douglas D. , Jongthammanurak Samerkhae , Liu Jifeng , Danielson David T. , Wada Kazumi , Michel Jurgen , Kimerling Lionel C. 
Published: June 2019

AbstractWe have fabricated the first CMOS process compatible high-responsivity Ge p-i-n diodes for 1.55 μm wavelengths. The thermal expansion mismatch between Ge epilayers and Si substrates was used to engineer tensile strain upon cooling from the growth temperature. This 0.2% tensile strain results in a lowering of the direct transition energy in Ge by 30 meV and extends the responsivity curve to near 1.6μm.
Prospects of Laser Operation in Erbium Doped Silicon
Authors: Huda M. Q. , Ali S. I. 
Published: June 2019

AbstractProspects of laser operation in erbium doped silicon has been analyzed by a Shockley-Read-Hall (SRH) model. Erbium atoms have been considered to be introducing strong recombination centers in the silicon lattice. Electron-hole recombination at these sites were considered to be the source of erbium excitation. A two level system was considered for calculation of optical gain and the laser threshold. For a laser cavity of 300 μm with mirror reflectivities of 90%, and an optimistic absorption coefficient of 5 cm-1, a population inversion of 1.4×1018/cm3 was estimated as the threshold value. Achievement of the lasing condition was found feasible, but only for certain conditions of erbium activation. Effects of nonradiative deexcitation routes have been analyzed. On the assumption of 1019/cm3 of active erbium sites, linear increase of optical power in the laser cavity has been estimated for injected carrier densities above 1018/cm3.
Coupling and Cooperative Up-conversion Coefficients in Er-doped Si Nanocrystals
Authors: Pacifici Domenico , Franzò Giorgia , Iacona Fabio , Priolo Francesco 
Published: June 2019

AbstractIn the present work, a quantitative understanding of the Er-doped Si nanocrystals interaction is reported. We present a model based on an energy level scheme taking into account the coupling between each Si nanocrystal and the neighboring Er ions. By fitting the steady state and time resolved luminescence signals at both the 1.54 and 0.98 μm Er lines we were able to determine a value of 3×10-15cm3s-1for the coupling coefficient. Moreover, a strong cooperative up-conversion mechanism, active between two excited Er ions and characterized by a coefficient of 7×10-17cm3s-1, will be shown to be active in the system, demonstrating that each Si nanocrystal can actually excite more than one Er ion.
Effect of Illumination on Organic Polymer Thin-Film Transistors
Authors: Hamilton Michael C. , Martin Sandrine , Kanicki Jerzy 
Published: June 2019

AbstractWe have investigated the effects of white-light illumination on the electrical performance of organic polymer thin-film transistors (OP-TFTs). The OFF-state drain current is significantly increased, while the drain current in the strong accumulation regime is relatively unaffected. At the same time, the threshold voltage is decreased and the subthreshold slope is increased, while the field-effect mobility of the charge carriers is not affected. The observed effects are explained in terms of the photogeneration of free charge carriers in the channel region due to the absorbed photons.
Pyrromethene dye doped optical polymers for amplifiers and lasers
Authors: Ramon M. , Bryden T. , Jones T.S. , Bradley D.D.C. 
Published: June 2019

AbstractPolymeric, planar waveguides of pyrromethene dye 1,3,5,7, 8-pentamethyl-2, 6-diethylpyrromethene-BF2 (PM567)-doped poly(methylmethacrylate) (PMMA) were prepared by spin coating (SC) and solution diffusion (SD) methods. Both techniques produced films that, under laser illumination, show strong spectral narrowing due to amplified spontaneous emission (ASE). Samples prepared by SD showed higher gain than the SC films. Also, compared to the SC samples, the smooth surface of the SD samples reduced scattering at the surface and therefore guding losses. The high dye concentration present in the SD samples may be responsible for the increased photostability (more than 105 pulses). The SD method appears to offer a simple alternative for the production of planar wave-guides for amplifier devices.
N- and P-Type Building Blocks for Organic Electronics Based on Oligothiophene Cores
Authors: Facchetti Antonio , Yoon Myung-Han , Katz Howard E. , Mushrush Melissa , Marks Tobin J. 
Published: June 2019

AbstractOrganic semiconductors exhibiting complementary-type carrier mobility are the key components for the development of the field of “gplastic electronics” We present here a novel series of α,ω- and isomerically pure ββ'-diperfluorohexyl-substituted thiophene and study the impact of fluoroalkyl substitution and conjugation length vis-a-vis the corresponding fluorinefree analogues. Trends between the fluorinated and fluorine-free families in molecular packing, HOMO-LUMO gap, and π-π interactions are found to be strikingly similar. TFT measurements indicate that all members of the fluorinated series are n-type semiconductors
Oligothiophene Organic Thin Film Transistors and Circuits
Authors: Halik Marcus , Klauk Hagen , Zschieschang Ute , Schmid Gunter , Ponomarenko Sergei A. , Kirchmeyer Stephan 
Published: June 2019

AbstractWe have investigated a series of α,α'-oligothiophenes with chromophore length ranging from four to six units, and with side chains comprised of ten, six, two, and zero alkyl units. We have fabricated top-contact and bottom-contact organic TFTs with thermally evaporated active layers and found that the TFT performance depends critically on the length of the side chains and on the contact configuration (with mobilities ranging from 0.07 to 1.1 cm2 / V-s), but is relatively insensitive to the chromophore length. We have also fabricated ring oscillators with didecylsexithiophene and measured a signal propagation delay of 30 μsec per stage. In addition, we have fabricated oligothiophene-TFTs with ultra-thin self-assembled monolayer (SAM) gate dielectrics, with the intent to evaluate if long alkyl side chains contribute usefully to the effective thickness of a SAM gate dielectric. We have measured carrier mobilities as large as 0.05 cm2 / V-s and subthreshold swing as low as 200 mV / decade.
Energy Transfer Studies of Polyphenylene-Type Polymers to a Series of Dyes.
Authors: Clancy Sean O. , Padmaperuma Asanga B. , Harper Aaron W. 
Published: June 2019

AbstractEnergy transfer from two polyphenylene-type polymers to a series of organic dyes was studied. One of the polymers was synthesized via Suzuki coupling of 1,4-phenyldiboronic acid with 1,4-dibromobenzene to obtain polyphenylene. The other polymer was a polybenzophenone generated by a nickel-mediated coupling of 2,5-dichloro-4'-methylbenzophenone. These polymers were used as the energy donors. A variety of Coumarins and other dyes were used as acceptors. Photophysical data and energy transfer parameters were determined.