bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Impact of Capping on the Mobility and Thermal Stability of Organic Thin Film Transistors
Authors: Meyer Stephan , Sellner Stefan , Schreiber Frank , Dosch Helmut , Ulbricht Gerhard , Fischer Matthias , Gompf Bruno , Pflaum Jens 
Published: April 2011

ABSTRACTWe performed temperature-dependent studies on pentacene thin film transistors (TFTs) with and without encapsulation. The capping layer is realized either by a sputtering layer of aluminum oxide (AlOx.) or, alternatively, by a polymeric layer of poly-para-xylylene (PPX). A field-effect can be demonstrated for both capping materials up to temperatures of about 140 – 170 °C, which is about 50 °C above the desorption point of uncapped pentacene thin films on SiO2 substrates. Complementary studies by thermal desorption spectroscopy and temperature dependent x-ray diffraction show that the organic layer remains crystalline on the substrate far above the electrical breakdown temperature of the encapsulated device.
Surface Modifications using Thiol Self-Assembled Monolayers on Au Electrodes in Organic Field Effect Transistors
Authors: Hiroshiba Nobuya , Kumashiro Ryotaro , Komatsu Naoya , Suto Yusuke , Ishii Hisao , Takaishi Shinya , Yamashita Masahiro , Tsukagoshi Kazuhiro , Tanigaki Katsumi 
Published: April 2011

ABSTRACTThe influences of self-assembled-monolayers (SAMs) modifications on the gold electrodes in organic field effect transistors are studied using benzen-thiols (BzTs) having amino (NH2), nitro (NO2) and methyl (CH3) substituents and pentacene as an organic semiconductor. The field effect transistor (FET) characteristics are found to be very sensitive to the preparation condition of the SAMs modified surfaces. This can be rationalized in terms of the barriers against carrier injections made by SAMs and this situation can be monitored using a surface contact-angle method. The enhancement in the field effect mobilities μ is observed when the SAMs modifications to the electrodes are applied, and this could be caused by the higher efficiency of carrier injection attained by the hole transfer from SAMs to pentacene molecules.
Formation of Porous Organosilicate Glasses Produced by PECVD and UV Treatment
Authors: O'Neill Mark L. , Du Lin-Shu , McDaniel Paula L. , Peterson Brian K. , Weigel Scott J. , Haas Mary K. , Vrtis Raymond N. , Sinatore Dino , Bitner Mark D. , Theodorou Kathleen E. , O'Neill Mark L. 
Published: April 2011

ABSTRACTThe deposition and post-treatment processes involved in the production of porous organosilicate glasses (OSGs) by plasma-enhanced chemical vapor deposition (PECVD) with ultraviolet light (UV) treatment are investigated through the use of a deuterated organic porogen precursor using infrared spectroscopy and solid-state nuclear magnetic resonance spectroscopy. Infrared analysis provides evidence for hydrogen-deuterium scrambling between the chemical species during the deposition process, which is exacerbated by the UV treatment process. Analysis of 13C cross-polarized magic angle spinning (CP-MAS) NMR suggests that the porogen exists in domains relatively isolated from the network, in agreement with short UV treatment time morphological data that indicates the pore size is relatively constant from the early stages of UV treatment process. The chemical and morphological information provides further support for a deposition controlled morphology and has implications towards enhanced chemical processing of porous organosilicate glass (OSG) films for back-end-of-line integrated circuit manufacturing.
Electrochemical Corrosion Inhibition System for Photoresist Stripper for New Copper FPD Manufacturing
Authors: Inaoka Seiji , Kim Sang In 
Published: April 2011

ABSTRACTDevelopment of photoresist stripper with copper compatibility is challenging as conventional corrosion inhibitors do not protect the metal as expected. Copper corrosion inhibition mechanism of newly developed photoresist stripper is proposed that significantly reduces copper corrosion with small amount of corrosion inhibitor.
Laser-Induced Microstructural Modification of Polycrystalline Cu and Ag Films Encapsulated in SiO2
Authors: Zhong Rong , Wiezorek Jorg M.K. , Leonard John P. 
Published: April 2011

ABSTRACTExcimer-laser-induced rapid lateral solidification was used to produce large grain microstructures in copper and silver thin films. These were multilayer thin film structures consisting of sputter deposited copper and silver thin films encapsulated by silica (SiO2/metal/SiO2/Si substrate). In this process, a single excimer laser pulse and projection imaging optics were used to melt a 60 micron wide line in the metal film. The resolidification of the melted lines is found to occur laterally in the plane of the film, resulting in grains greater than 20 um in length and 1 um wide. Electron diffraction analysis allowed identification of a strong <001> texture in the growth direction along the major axis of the elongated grains as well as similar texture parallel to the film surface. Various dislocation and faulted defect structures are identified and examined in the context of the rapid solidification and potential application to interconnects.
Low Temperature Direct Metal Bonding by Self Assembled Monolayers
Authors: Ang Xiaofang , Chin Li Cheong , Zhang Guo Ge , Wei Jun , Chen Zhong , Wong Chee Cheong 
Published: April 2011

ABSTRACTElevated bonding temperature for interconnection deteriorates the reliability of both the device and the interconnect; hence the imperative for developing low temperature bonding methods. This study investigates the feasibility of using self-assembled monolayers (SAMs) to assist direct gold-gold bonding. This involves a simple molecular self-assembly process whereby a monolayer of alkyl chains with a sulfur end group is attached to the gold surface prior to thermocompression bonding. Using this method, we have achieved gold to gold bonding at a bonding temperature below 100°C, a significant reduction compared to the conventional bonding temperatures of above 150 °C. We attribute this temperature reduction to two properties of SAMs - (1) surface passivation of the Au surface that precludes adsorption of surface contaminants, and (2) The easy displacement of SAMs through thermal desorption just before bonding occurs. This SAMs-assisted bonding mechanism is supported by X-ray photoelectron spectroscopy (XPS) and surface plasmon resonance (SPR) results.
Charging Model of a Si Nanocrystal-based Floating Gate in a Quantum Flash Memory
Authors: Leriche Bertrand , Leroy Yann , Cordan Anne-Sophie 
Published: April 2011

AbstractWe propose a theoretical study for charging the floating gate composed of Si nanocrystals (NCs), in a non-volatile flash memory. Only a few electrons tunnel from the channel of a metal-oxide-semiconductor transistor into the two-dimensional array of nanocrystals.Our model is based on the geometrical and physical properties of the device, in order to take the dispersion of the relevant parameters into account: NC radii, inter-NC distances, tunnel oxide and gate oxide thicknesses. The energy subbands of the channel are explicitly included, together with the doping density.This three-dimensional model of electron tunneling into a NC is numerically solved through a two-dimensional finite element approach, which allows extensive numerical experimentations.The tunneling times to charge a single NC or the whole NC floating gate are evaluated in a finer detail, and the influence of the dispersion of the relevant parameters is discussed.Such a study may help the experimentalists to build efficient quantum flash memories.
No Interfacial Layer for PEDOT Electrodes on PVDF: Characterization of Reactions at the Interface P(VDF/TrFE)/Al and P(VDF/TrFE)/PEDOT:PSS
Authors: Mueller Klaus , Mandal Dipanka , Schmeisser Dieter 
Published: April 2011

AbstractWith photoelectron spectroscopy, we study the interface chemistry of the copolymer poly(vinylidene fluoride trifluoroethylene) (P(VDF-TrFE)) and different electrode materials. We compare the interfaces aluminum/P(VDF-TrFE) and PEDOT:PSS/P(VDF-TrFE). PEDOT:PSS is a conductive polymer (Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)). The data sug-gest that we have an interface layer for electrodes, made of aluminum. An interface reaction occurs in both cases: for aluminum as top and as bottom electrode. In contrast, the organic PE-DOT:PSS electrode shows no chemical interaction with the P(VDF-TrFE) polymer. The much lower reactivity of organic electrodes, compared to aluminum, gives a direct hint to im-proved functional properties of thin organic ferroelectric films.
Study of Band Alignment at CBD-CdS/Cu(In1-xGax)Se2 (x = 0.2 - 1.0) Interfaces by Photoemission and Inverse Photoemission Spectroscopy
Authors: Teshima Shimpei , Kashiwabara Hirotake , Masamoto Keimei , Kikunaga Kazuya , Takeshita Kazunori , Okuda Tetsuji , Sakurai Keiichiro , Ishizuka Shogo , Yamada Akimasa , Matsubara Koji , Niki Shigeru , Yoshimura Yukio , Terada Norio 
Published: April 2011

AbstractDependence of band alignments at interfaces between CdS by chemical bath deposition and Cu(In1-xGax)Se2 by conventional 3-stage co-evaporation on Ga substitution ratio x from 0.2 to 1.0 has been systematically studied by means of photoemission spectroscopy (PES) and inverse photoemission spectroscopy (IPES). For the specimens of the In-rich CIGS, conduction band minimum (CBM) by CIGS was lower than that of CdS. Conduction band offset of them was positive about +0.3 ~ +0.4 eV. Almost flat conduction band alignment was realized at x = 0.4 ~ 0.5. On the other hand, at the interfaces over the Ga-rich CIGS, CBM of CIGS was higher than that of CdS, and CBO became negative. The present study reveals that the decrease of CBO with a rise of x presents over the wide rage of x, which results in the sign change of CBO around 0.4 ~ 0.45. In the Ga-rich interfaces, the minimum of band gap energy, which corresponded to energy spacing between CBM of CdS and valence band maximum of CIGS, was almost identical against the change of band gap energy of CIGS. Additionally, local accumulation of oxygen related impurities was observed at the Ga-rich samples, which might cause the local rise of band edges in central region of the interface.
Metastable Defect Distributions in CIGS Solar Cells and Their Impact on Device Efficiency
Authors: Igalson Malgorzata 
Published: April 2011

AbstractMetastabilities in the electrical characteristics of CIGS devices are commonly observed phenomena originating from persistent changes of shallow and deep levels distributions within the absorber. We examine characteristic changes induced by voltage bias and light together with their relaxation behavior and interpret them as the consequences of a negative-U type of centers predicted by theoretical calculations of Lany and Zunger. It is shown how the properties of these centers justify a model of p+ layer explaining specific features of light and dark current-voltage characteristics. The discussion showing the impact of various charge distributions on carrier transport is presented. The arguments are provided, that centers responsible for metastable effects are also to blame for majority of photovoltaic losses exhibited in various devices.
Variable Light Soaking Effect of Cu(In,Ga)Se2 Solar Cells with Conduction Band Offset Control of Window/Cu(In,Ga)Se2 Layers
Authors: Minemoto Takashi , Hashimoto Yasuhiro , Satoh Takuya , Negami Takayuki , Takakura Hideyuki 
Published: April 2011

AbstractThe impact of the conduction band offset (CBO) between window/Cu(In,Ga)Se2 (CIGS) layers on the light soaking (LS) effect in CIGS solar cells has been studied with continuous CBO control using a (Zn,Mg)O (ZMO) window layer. Two types of CIGS solar cells with different window/buffer/absorber layers configurations were fabricated, i.e., ZMO/CIGS (without buffer layer) and ZMO/CdS/CIGS structures. The CBO values between ZMO and CIGS layers were controlled to -0.15~0.25 eV. Plus and minus signs of CBO indicate the conduction band minimums of ZMO above and below that of CIGS, respectively. Current-voltage (J-V) characteristics of the solar cells with different LS durations revealed that a positive CBO value higher than 0.16 eV induces J-V curve distortion, i.e., LS effect, and all the J-V characteristics stabilized in 30 min. The degrees of the LS effect were dominated by the CBO value between ZMO and CIGS layers in the both structure regardless of the existence of CdS buffer layers. These results indicate that the LS effect is dominated by the highest barrier for photo-generated electrons in the conduction band diagram, i.e., the CBO between ZMO and CIGS layers, and quantitatively the LS effect emerges the CBO value higher than 0.16 eV.
Highly Arsenic Doped CdTe Layers for the Back Contacts of CdTe Solar Cells
Authors: Barrioz Vincent , Proskuryakov Yuri Y. , Jones Eurig W. , Major Jon D. , Irvine Stuart J.C. , Durose Ken , Lamb Dan A. 
Published: April 2011

AbstractIn an effort to overcome the lack of a suitable metal as an ohmic back contact for CdTe solar cells, a study was carried out on the potential for using a highly arsenic (As) doped CdTe layer with metallization. The deposition of full CdTe/CdS devices, including the highly doped CdTe:As and the CdCl2 treatment, were carried out by metal organic chemical vapour deposition (MOCVD), in an all-in-one process with no etching being necessary. They were characterized and compared to control devices prepared using conventional bromine-methanol back contact etching. SIMS and C-V profiling results indicated that arsenic concentrations of up to 1.5 × 1019 at·cm-3 were incorporated in the CdTe. Current-voltage (J-V) characteristics showed strong improvements, particularly in the open-circuit voltage (Voc) and series resistance (Rs): With a 250 nm thick doped layer, the series resistance was reduced from 9.8 Ω·cm2 to 1.6 Ω·cm2 for a contact area of 0.25 cm2; the J-V curves displayed no rollover, while the Voc increased by up to 70 mV (~ 12 % rise). Preliminary XRD data show that there may be an As2Te3 layer at the CdTe surface which could be contributing to the low barrier height of this contact.
Cu(In,Ga)Se2 Prepared from Electrodeposited CuGaSe2/CuInSe2 Bilayer for Solar Cell Applications
Authors: Oda Yusuke , Minemoto Takashi , Takakura Hideyuki , Hamakawa Yoshihiro 
Published: April 2011

AbstractWe report the preparation of Cu(In,Ga)Se2 (CIGS) thin-films using the electrodeposited (ED) CuGaSe2 (CGS)/CuInSe2 (CIS) bilayers. CGS/CIS bilayers were prepared on soda-lime glass /Mo substrates to realize the controlled Ga/(Ga+In) ratios and smooth layers of CIGS thin-films. It was found that the composition and morphology of CGS films was highly dependent on the composition of the bath. Crack-free and morphological CGS thin-films were obtained by the addition of supporting electrolyte and brightener. For the morphology and the crystallization of the ED-CIGS films, the best electric charges of CGS and CIS films were 1.0 C and 6.0 C respectively and the films were annealed at 600 oC for 60 min. However, the interface of the ED-CGS/CIS film had some voids and interdiffusions of Ga and In did not take place by annealing. The CIGS solar cell using ED-CGS/CIS films as an absorber exhibited diode behavior.
Study of Gold Thin Films Evaporated on Polyethylene Naphthalate Films toward the Fabrication of Quantum Cross Devices
Authors: Kaiju Hideo , Ono Akito , Kawaguchi Nobuyoshi , Kondo Kenji , Ishibashi Akira 
Published: April 2011

AbstractMolecular electronics devices continue to be pursued as a technology that offers the prospect of scaling device dimensions down to a few nanometers and also promote a practical introduction for high-density memory applications. One of several molecular devices is a cross-bar memory device fabricated by nanoimprint lithography process, which has achieved the production of 30-nm half-pitch patterning. However, today's production procedures such as nanoimprint lithography, optical lithography, and electron-beam lithography, do not allow for the resolution to achieve sub-10-nm line-width structures. Recently we have proposed a double nano-“baumkuchen” (DNB) structure, composed of two thin slices of alternating metal/insulator nano-“baumkuchen” as a lithography-free nano-structure fabrication technology. The DNB has potential application in a high-density memory device, the cross point of which can scale down to ultimately a few nanometers feature sizes because the pattering resolution is determined by the metal-deposition rate, ranging from 0.01 nm/s to the order of 0.1 nm/s. One element of the DNB structure is called a quantum cross (QC) device that consists of two metal nano-ribbons having edge-to-edge configuration. In the area of edge-to-edge QC devices there has been no experimental reports, meanwhile face-to-face devices such as cross-bar devices and spin tunneling devices, have been widely studied both theoretically and experimentally. In our present work, as the first experimental attempt toward the fabrication of QC devices, we have studied gold thin films evaporated on polyethylene naphtalate (PEN) organic films, which can be a candidate of metal/insulator part used for QC devices, by using the atomic force microscope (AFM). Au thin films were thermally evaporated on PEN films in the high vacuum chamber including the film-rolled-up system. The Au thickness was measured by a mechanical method using the stylus surface profiler and an optical method using the diode pumped solid state (DPSS) green laser. Surface morphologies of Au thin films on PEN films were analyzed by the AFM at room temperature. As the thickness of Au films evaporated on PEN films decreases from 20 nm to 5 nm, the AFM surface roughness is reduced from 4.8 nm down to 1.5 nm in the scanning area of 500~500 nm2. The Au grain size is 28.0-4.6 nm for 5-nm-thick Au films and 45.8-5.8 nm for 10-nm-thick Au films, respectively. As a result of the scaling investigation of the surface roughness, the surface roughness of 5-nm-thick Au films is 0.22 nm, corresponding to one atomic size, in the scanning scale of 5 nm. These experimental results indicate that Au thin films on PEN films are suitable as a candidate of metal/insulator(organic films) hybrid materials used for QC devices, and may open up a noble research field to clarify the electric characterization of QC devices using a few atoms or molecules leading to high-density memories.
Mechanical Evaluation of Thermal Transitions in Polymer Nanofibres Using SPM
Authors: Wang Wei , Li Shuangwu , Barber Asa H. 
Published: April 2011

AbstractPolymer nanofibres produced by electrospinning techniques have unique mechanical properties due to their large surface area to volume ratio and potentially high molecular orientation. The effects of temperature on mechanical properties is challenging to measure due to the small fibre diameters produced. In this paper, scanning probe microscopy (SPM) is successfully used to elucidate the mechanical performance of individual electrospun polyvinyl alcohol (PVA) nanofibres over a range of temperatures. As observed in the results, thermal transitions have a dramatic effect on the mechanical behaviour of the nanofibres and are highlighted using SPM techniques analogous to dynamic mechanical thermal analysis but at the nanoscale. Interestingly, nanofibre thermal transitions are shown to be mediated by fibre diameter and the driving force of reducing the surface area of the nanofibre.
Nanoscale Analysis of Defects in Semiconductors and Dielectrics by Means of Charge-transient Spectroscopy/microscopy
Authors: Lányi Štefan , Nádaždy Vojtech , Hruškovic Miloslav , Hribik Ján 
Published: April 2011

AbstractWe discuss the possibilities of analysis of electrically active defects in semiconductors and dielectrics by means of Isothermal Capacitance-Transient Spectroscopy and Isothermal Charge-Transient Spectroscopy, applied on sub-micrometer scale. While the first of them utilizes the relaxation of the depletion layer, caused by emission of trapped charges and requires sufficient conductivity, the second directly integrates the transient current and can be applied also to low-conductivity materials like dielectrics.We present some results obtained on pentacene thin films. By means of our charge-transient spectrometer we have achieved a resolution of hundreds of electrons but we believe it can be further improved approximately by one order of magnitude. In materials with relatively high defect concentration, using optimal shape of the probe, a resolution on the order of tens of manometers can be achieved. At low defect concentrations, e.g. in device quality silicon, a resolution on the hundred-nm level is expected.
Sublimation Growth and Defect Characterization of AlN Single Crystals
Authors: Wang Shaoping , Raghothamachar Balaji , Dudley Michael , Ren Zaiyuan , Han Jung , Timmerman Andrew G. 
Published: April 2011

AbstractIn this paper, we report results from AlN single crystal growth experiments using a sublimation physical vapor transport growth technique. AlN single crystal boules up to 7mm in diameter were demonstrated. Characterization of polished AlN single crystal samples was carried out using various techniques, including synchrotron X-ray topography.
“For Whom the Bell Tolls” Mexican Copper Bells from the Templo Mayor Offerings: Analysis of the Production Process and its Cultural Context
Authors: Schulze Niklas 
Published: April 2011

AbstractThe 3389 copper (alloy) bells from offerings included in successive building phases of Late Postclassic Templo Mayor (A.D. 1325 – 1520) of Tenochtitlan (Mexico City) are the results of production processes influenced by social, economic, ideological and technological factors. The compositional and morphological variability of the bells in the earlier construction phases of the Templo Mayor suggests the presence of several workshops in or around Tenochtitlan, while the reduction of this spectrum on one bell type made of copper-tin bronze, points towards a standardization of the production process and a decrease in the number of workshops that supplied the Templo Mayor in later phases. The compositional and morphological information, as well as contextual analysis and comparison with other Mexican bells, give insights into the bells' symbolism, the mechanisms used to supply the Templo Mayor with offerings, the organization of metalwork and the rationale behind some of the technological choices of the artisans. The detected changes through time seem to point to important shifts in the social, technological, economic and ideological influences on the choices of the artisans in the latter half of Aztec rule.
Painted Decoration Studies in a Fourth Century BC Vergina Tomb
Authors: Pavlidou Eleni , Kyriakou A. , Mirtsou E. , Anastasiou L. , Zorba T. , Hatzikraniotis E. , Paraskevopoulos K. M. 
Published: April 2011

AbstractAegae, the first capital of the Macedonians, in Northern Greece, is being excavated since 1938. The most impressive finds come from the unlooted tombs of the Great Tumulus, where the grave of Philip II, father of Alexander the Great, was discovered. Not far from the Great Tumulus, in the “Tumuli cemetery”, the most ancient part of the graveyard (1000-700 B.C.), recent excavations brought to light three looted graves dated in the mid-fourth century B.C., with very interesting finds such as weapons, gilded wreaths, pieces of jewelry, remains of decoration of wooden furniture, ceramic vases broken in small pieces and wall paintings. This paper describes studies carried out on the binding and the painting materials used for the decoration of the above wall paintings and ceramic vases. The characterization was performed through Optical Microscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Microscopy (SEM-EDS). It was found that the fresco technique was used, while all the pigments were identified. The results are discussed and related with other findings in that period in the Greek area