In-situ detection of defect formation in organic flexible electronics by Kelvin Probe Force Microscopy

Organic semiconductor technology has attracted considerable research interest in view of its great promise for large area, lightweight, and flexible electronics applications. Owing to their advantages in processing and unique physical properties, organic semiconductors can bring exciting new opportunities for broad-impact applications requiring large area coverage, mechanical flexibility, low-temperature processing, and low cost. In order to achieve highly flexible device architecture it is crucial to understand on a microscopic scale how mechanical deformation affects the electrical performance of organic thin film devices. Towards this aim, I established in this thesis the experimental technique of Kelvin Probe Force Microscopy (KPFM) as a tool to investigate the morphology and the surface potential of organic semiconducting thin films under mechanical strain. KPFM has been employed to investigate the strain response of two different Organic Thin Film Transistor with active layer made by 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-Pentacene), and Poly(3-hexylthiophene-2,5-diyl) (P3HT). The results show that this technique allows to investigate on a microscopic scale failure of flexible TFT with this kind of materials during bending. I find that the abrupt reduction of TIPS-pentacene device performance at critical bending radii is related to the formation of nano-cracks in the microcrystal morphology, easily identified due to the abrupt variation in surface potential caused by local increase in resistance. Numerical simulation of the bending mechanics of the transistor structure further identifies the mechanical strain exerted on the TIPS-pentacene micro-crystals as the fundamental origin of fracture. Instead for P3HT based transistors no significant reduction in electrical performance is observed during bending. This finding is attributed to the amorphous nature of the polymer giving rise to an elastic response without the occurrence of crack formation.

Growth, modification and integration of carbon nanotubes into molecular electronics

Molecules are the smallest possible elements for electronic devices, with active elements for such devices typically a few Angstroms in footprint area. Owing to the possibility of producing ultrahigh density devices, tremendous effort has been invested in producing electronic junctions by using various types of molecules. The major issues for molecular electronics include (1) developing an effective scheme to connect molecules with the present micro- and nano-technology, (2) increasing the lifetime and stabilities of the devices, and (3) increasing their performance in comparison to the state-of-the-art devices. In this work, we attempt to use carbon nanotubes (CNTs) as the interconnecting nanoelectrodes between molecules and microelectrodes. The ultimate goal is to use two individual CNTs to sandwich molecules in a cross-bar configuration while having these CNTs connected with microelectrodes such that the junction displays the electronic character of the molecule chosen. We have successfully developed an effective scheme to connect molecules with CNTs, which is scalable to arrays of molecular electronic devices. To realize this far reaching goal, the following technical topics have been investigated. 1. Synthesis of multi-walled carbon nanotubes (MWCNTs) by thermal chemical vapor deposition (T-CVD) and plasma-enhanced chemical vapor deposition (PECVD) techniques (Chapter 3). We have evaluated the potential use of tubular and bamboo-like MWCNTs grown by T-CVD and PE-CVD in terms of their structural properties. 2. Horizontal dispersion of MWCNTs with and without surfactants, and the integration of MWCNTs to microelectrodes using deposition by dielectrophoresis (DEP) (Chapter 4). We have systematically studied the use of surfactant molecules to disperse and horizontally align MWCNTs on substrates. In addition, DEP is shown to produce impurityfree placement of MWCNTs, forming connections between microelectrodes. We demonstrate the deposition density is tunable by both AC field strength and AC field frequency. 3. Etching of MWCNTs for the impurity-free nanoelectrodes (Chapter 5). We show that the residual Ni catalyst on MWCNTs can be removed by acid etching; the tip removal and collapsing of tubes into pyramids enhances the stability of field emission from the tube arrays. The acid-etching process can be used to functionalize the MWCNTs, which was used to make our initial CNT-nanoelectrode glucose sensors. Finally, lessons learned trying to perform spectroscopic analysis of the functionalized MWCNTs were vital for designing our final devices. 4. Molecular junction design and electrochemical synthesis of biphenyl molecules on carbon microelectrodes for all-carbon molecular devices (Chapter 6). Utilizing the experience gained on the work done so far, our final device design is described. We demonstrate the capability of preparing patterned glassy carbon films to serve as the bottom electrode in the new geometry. However, the molecular switching behavior of biphenyl was not observed by scanning tunneling microscopy (STM), mercury drop or fabricated glassy carbon/biphenyl/MWCNT junctions. Either the density of these molecules is not optimum for effective integration of devices using MWCNTs as the nanoelectrodes, or an electroactive contaminant was reduced instead of the ionic biphenyl species. 5. Self-assembly of octadecanethiol (ODT) molecules on gold microelectrodes for functional molecular devices (Chapter 7). We have realized an effective scheme to produce Au/ODT/MWCNT junctions by spanning MWCNTs across ODT-functionalized microelectrodes. A percentage of the resulting junctions retain the expected character of an ODT monolayer. While the process is not yet optimized, our successful junctions show that molecular electronic devices can be fabricated using simple processes such as photolithography, self-assembled monolayers and dielectrophoresis.

DESIGN AND IMPLEMENTATION OF HOME USE PORTABLE SMART ELECTRONICS

The widespread of low cost embedded electronics makes it easier to implement the smart devices that can understand either the environment or the user behaviors. The main object of this project is to design and implement home use portable smart electronics, including the portable monitoring device for home and office security and the portable 3D mouse for convenient use. Both devices in this project use the MPU6050 which contains a 3 axis accelerometer and a 3 axis gyroscope to sense the inertial motion of the door or the human hands movement. For the portable monitoring device for home and office security, MPU6050 is used to sense the door (either home front door or cabinet door) movement through the gyroscope, and Raspberry Pi is then used to process the data it receives from MPU6050, if the data value exceeds the preset threshold, Raspberry Pi would control the USB Webcam to take a picture and then send out an alert email with the picture to the user. The advantage of this device is that it is a small size portable stand-alone device with its own power source, it is easy to implement, really cheap for residential use, and energy efficient with instantaneous alert. For the 3D mouse, the MPU6050 would use both the accelerometer and gyroscope to sense user hands movement, the data are processed by MSP430G2553 through a digital smooth filter and a complementary filter, and then the filtered data will pass to the personal computer through the serial COM port. By applying the cursor movement equation in the PC driver, this device can work great as a mouse with acceptable accuracy. Compared to the normal optical mouse we are using, this mouse does not need any working surface, with the use of the smooth and complementary filter, it has certain accuracy for normal use, and it is easy to be extended to a portable mouse as small as a finger ring.

Directed Metalation Cascade To Access Highly Functionalized Thieno2,3-fbenzofuran and Exploration as Building Blocks for Organic Electronics

A tandem directed metalation has been successfully applied to the preparation of thieno2,3-fbenzofuran-4,8-dione, providing an efficient and facile approach to symmetrically and unsymmetrically functionalize the thieno2,3-fbenzofuran core at the 2,6 positions as well as to introduce the electron-withdrawing or -donating groups (EWG or EDG) at its 4,8 positions. The presence of various functional groups makes late-stage derivatization attainable.

Performance of cryogenic charge readout electronics with the ARGONTUBE LAr TPC

ARGONTUBE is a liquid argon time projection chamber (TPC) with an electron drift length of up to 5 m equipped with cryogenic charge-sensitive preamplifiers. In this work, we present results on its performance, including a comparison of the new cryogenic charge-sensitive preamplifiers with the previously used room-temperature-operated charge preamplifiers.

Texas electronics waste management: A policy analysis for the 21st century

Electronic waste is a fairly new and largely unknown phenomenon. Accordingly, governments have only recently acknowledged electronic waste as a threat to the environment and public health. In attempting to mitigate the hazards associated with this rapidly growing toxic waste stream, governments at all levels have started to implement e-waste management programs. The legislation enacted to create these programs is based on extended producer responsibility or EPR policy. ^ EPR shifts the burden of final disposal of e-waste from the consumer or municipal solid waste system to the manufacturer of electronic equipment. Applying an EPR policy is intended to send signals up the production chain to the manufacturer. The desired outcome is to change the methods of production in order to reduce production outputs/inputs with the ultimate goal of changing product design. This thesis performs a policy analysis of the current e-waste policies at the federal and state level of government, focusing specifically on Texas e-waste policies. ^ The Texas e-waste law known, as HB 2714 or the Texas Computer TakeBack Law, requires manufacturers to provide individual consumers with a free and convenient method for returning their used computers to manufacturers. The law is based on individual producer responsibility and shared responsibility among consumer, retailers, recyclers, and the TCEQ. ^ Using a set of evaluation criteria created by the Organization for Economic Co-operation and Development, the Texas e-waste law was examined to determine its effectiveness at reducing the threat of e-waste in Texas. Based on the outcomes of the analysis certain recommendations were made for the legislature to incorporate into HB 2714. ^ The results of the policy analysis show that HB 2714 is a poorly constructed law and does not provide the desired results seen in other states with EPR policies. The TakeBack Law does little to change the collection methods of manufacturers and even less to change their production habits. If the e-waste problem is to be taken seriously, HB 2714 must be amended to reflect the proposed changes in this thesis.^

Diverging Development Paths of the Electronics Industry in Korea and Taiwan

This paper examines the process and mechanism of economic development in the Republic of Korea and Taiwan through a comparative analysis of the electronics industry in each country. The paper will show that in its initial stage of development, the electronics industry in both economies had the same type of dual structure: a domestic demand sector based on the protected domestic market, and an export sector intended to capitalize on low-wage labor for the international market. However, this dual structure in the two economies faded away after the mid-1970s as their respective indigenous export-oriented enterprises began to develop. But the primary industrial players in each economy were very different. In Korea they were comprehensive electronics manufacturers affiliated with chaebols, and in Taiwan they were small and medium-size enterprises. Differences in the two economies' development mechanisms have brought about this divergence in development paths. In Korea this mechanism has been characterized by the government's positive role and the chaebol's readiness to react to the government's leadership. In Taiwan the development mechanism has been based on the private sector independent from the government. As an extension of such diverged development paths, ICs and personal computers showed spectacular growth in Korea and Taiwan after the 1980s. The development of ICs in Korea was primarily the result of a decisive role played by the chaebol's sizable financial resources, while the competitiveness in personal computers largely reflected the agility and flexibility of Taiwanese small and medium-size enterprises.

Trade, Exchange Rates, and Macroeconomic Dynamics in East Asia: Why the Electronics Cycle Matters

Against the background of increasing regional trade and investment, there is growing interest in monetary and macroeconomic policy coordination in East Asia. Although there is a sizable literature on macroeconomic linkages among East Asian countries and the potential merit of policy coordination in the region, the existing studies tend to examine these issues exclusively in terms of macroeconomic variables and do not consider how these aggregate variables are influenced by one prominent feature of a number of East Asian economies: their heavy dependence on the electronics industry. Although active engagement in the global electronics industry has been a powerful growth engine for the Asian countries, it has also left their economies vulnerable to cyclical fluctuations in the world electronics market. As the cycle of the global electronics industry exerts profound impacts on the medium-term dynamics of the Asian economies, it is imperative to take an explicit account of its influence when studying the way in which the regional economies are linked to one another and how this relationship can be altered by a specific policy initiative. We illustrate the importance of this point by examining recent studies on: (1) trade competition between China andother Asian countries and the role of the Chinese renminbi therein; and (2) the effect offluctuations in the yen/dollar exchange rate on the regional economies.

Empirical global value chain analysis in electronics and automobile industries :An application of Asian international input-output tables

This study aims to examine the international value distribution structure among major East Asian economies and the US. The mainstream trade theory explains the gains from trade; however, global value chain (GVC) approach emphasises uneven benefits of globalization among trading partners. The present study is mainly based on this view, examining which economy gains the most and which the least from the East Asian production networks. Two key industries, i.e., electronics and automobile, are our principle focus. Input-output method is employed to trace the creation and flows of value-added within the region. A striking fact is that some ASEAN economies increasingly reduce their shares of value-added, taken by developed countries, particularly by Japan. Policy implications are discussed in the final section.

Formation of supply chain collaboration and firm performance in the Thai automotive and electronics industries

This paper examines factors that encourage firms to go into supply chain collaborations (SCC) and relationships between SCC and supply chain performances (SCP), using a questionnaire survey on Thai automotive and electronics industries in 2012. OLS regression results show firms established supplier evaluation and audit system, system of rewards for high-performance supplier and long-term transactions with their supply chain partners under a competitive pressure are more closely cooperate with these partners on information sharing and decision synchronization. Instrumental variables regression indicates SCC arisen from competitive pressure, supplier evaluation and audit, a system of rewards for high-performance supplier and long-term relationship causally influence SCP such as on-time delivery, responsiveness to fast procurement, flexibility to customer need, and profit.

Supply chain collaboration and responsiveness : a comparison between Thai automotive and electronics industries

This paper examines factors that promote firms to develop supply chain collaborations (SCC) with their partners and relationships between SCC and supply chain operational performances (SCOP), using a questionnaire survey on Thai automotive and electronics industries in 2012. This paper also carries out a comparative study on these questions between the electronics and automotive industries. Two-stage least squares (2SLS) regressions verifY that supplier evaluation and audit is a foundation for firms to share information and synchronize decision makings with their partners, and that such SCC are significantly related to SCOP indictors such as on-time delivery, fast procurement, and flexibility to customer need irrespective of industry type. On the other hand, competitive pressure motivates only electronics firms to develop sec in order to be more innovative.

Methodologies for implement video decoders over multiprocessor platforms

The latest video coding standards developed, like HEVC (High Efficiency Video Coding, approved in January 2013), require for their implementation the use of devices able to support a high computational load. Considering that currently it is not enough the usage of one unique Digital Signal Processor (DSP), multicore devices have appeared recently in the market. However, due to its novelty, the working methodology that allows produce solutions for these configurations is in a very initial state, since currently the most part of the work needs to be performed manually. In consequence, the objective set consists on finding methodologies that ease this process. The study has been focused on extend a methodology, under development, for the generation of solutions for PCs and embedded systems. During this study, the standards RVC (Reconfigurable Video Coding) and HEVC have been employed, as well as DSPs of the Texas Instruments company. In its development, it has been tried to address all the factors that influence both the development and deployment of these new implementations of video decoders, ranging from tools up to aspects of the partitioning of algorithms, without this can cause a drop in application performance. The results of this study are the description of the employed methodology, the characterization of the software migration process and performance measurements for the HEVC standard in an RVC-based implementation. RESUMEN Los estándares de codificación de vídeo desarrollados más recientemente, como HEVC (High Efficiency Video Coding, aprobado en enero de 2013), requieren para su implementación el uso de dispositivos capaces de soportar una elevada carga computacional. Teniendo en cuenta que actualmente no es suficiente con utilizar un único Procesador Digital de Señal (DSP), han aparecido recientemente dispositivos multinúcleo en el mercado. Sin embargo, debido a su novedad, la metodología de trabajo que permite elaborar soluciones para tales configuraciones se encuentra en un estado muy inicial, ya que actualmente la mayor parte del trabajo debe realizarse manualmente. En consecuencia, el objetivo marcado consiste en encontrar metodologías que faciliten este proceso. El estudio se ha centrado en extender una metodología, en desarrollo, para la generación de soluciones para PC y sistemas empotrados. Durante dicho estudio se han empleado los estándares RVC (Reconfigurable Video Coding) y HEVC, así como DSPs de la compañía Texas Instruments. En su desarrollo se ha tratado de atender a todos los factores que influyen tanto en el desarrollo como en la puesta en marcha de estas nuevas implementaciones de descodificadores de vídeo; abarcando desde las herramientas a utilizar hasta aspectos del particionado de los algoritmos, sin que por ello se produzca una reducción en el rendimiento de las aplicaciones. Los resultados de este estudio son una descripción de la metodología empleada, la caracterización del proceso de migración de software, y medidas de rendimiento para el estándar HEVC en una implementación basada en RVC.

Energy Management and Optimization for Video Decoders based on Functional-oriented Reconfiguration

In recent years, the increasing sophistication of embedded multimedia systems and wireless communication technologies has promoted a widespread utilization of video streaming applications. It has been reported in 2013 that youngsters, aged between 13 and 24, spend around 16.7 hours a week watching online video through social media, business websites, and video streaming sites. Video applications have already been blended into people daily life. Traditionally, video streaming research has focused on performance improvement, namely throughput increase and response time reduction. However, most mobile devices are battery-powered, a technology that grows at a much slower pace than either multimedia or hardware developments. Since battery developments cannot satisfy expanding power demand of mobile devices, research interests on video applications technology has attracted more attention to achieve energy-efficient designs. How to efficiently use the limited battery energy budget becomes a major research challenge. In addition, next generation video standards impel to diversification and personalization. Therefore, it is desirable to have mechanisms to implement energy optimizations with greater flexibility and scalability. In this context, the main goal of this dissertation is to find an energy management and optimization mechanism to reduce the energy consumption of video decoders based on the idea of functional-oriented reconfiguration. System battery life is prolonged as the result of a trade-off between energy consumption and video quality. Functional-oriented reconfiguration takes advantage of the similarities among standards to build video decoders reconnecting existing functional units. If a feedback channel from the decoder to the encoder is available, the former can signal the latter changes in either the encoding parameters or the encoding algorithms for energy-saving adaption. The proposed energy optimization and management mechanism is carried out at the decoder end. This mechanism consists of an energy-aware manager, implemented as an additional block of the reconfiguration engine, an energy estimator, integrated into the decoder, and, if available, a feedback channel connected to the encoder end. The energy-aware manager checks the battery level, selects the new decoder description and signals to build a new decoder to the reconfiguration engine. It is worth noting that the analysis of the energy consumption is fundamental for the success of the energy management and optimization mechanism. In this thesis, an energy estimation method driven by platform event monitoring is proposed. In addition, an event filter is suggested to automate the selection of the most appropriate events that affect the energy consumption. At last, a detailed study on the influence of the training data on the model accuracy is presented. The modeling methodology of the energy estimator has been evaluated on different underlying platforms, single-core and multi-core, with different characteristics of workload. All the results show a good accuracy and low on-line computation overhead. The required modifications on the reconfiguration engine to implement the energy-aware manager have been assessed under different scenarios. The results indicate a possibility to lengthen the battery lifetime of the system in two different use-cases.