Processing Oxide Thin Films With Light

High-throughput roll-to-roll manufacturing of solution-deposited metal oxide electronics has the potential to enable the widespread and low-cost availability of thin film electronic devices including solar panels, large-area displays and lighting, and flexible medical devices and sensors. However, several challenges have prevented the realization of this potential: (1) The processing speed of solution-deposited oxides is severely limited by the length of the annealing process, usually greater than 20 minutes, which is typically necessary to convert solution-deposited precursor films into metal oxides, (2) the quality of the resultant metal oxide films is limited by the low upper operating temperatures of low-cost, roll-to-roll compatible, plastic substrates, typically much less than 250 °C, and (3) equilibrium heating of devices to these temperatures often results in mechanical failure of the thin films due to the different thermal responses of the films and substrates. In this dissertation, we address these challenges by using light, rather than heat, as a source of energy for curing solution-deposited metal oxide thin films. We use this method to develop solution-deposited oxide thin film transistors (TFTs) on shape memory polymer (SMP) substrates. We demonstrate the direct patterning of Al2O3 and In2O3 precursor films on SMP by exposure to UV light through a shadow mask as a method to overcome the mechanical failure of blanket-coverage films during thermal annealing. The patterned precursors are then converted to oxides for the gate dielectric and the channel semiconductor of the TFTs by thermal annealing without causing damage to the films. The unexpectedly high mobility displayed by these TFTs is studied and the absorption of water from the atmosphere by the gate dielectric is identified as the cause. Finally, we demonstrate the high-speed photonic curing of ZrO2 dielectric films on polyethylene naphthalate substrates. Using intense pulsed light to both heat and cure the oxide film in as little as 100 milliseconds without significantly heating the substrate, we achieve a process for fabricating metal oxide electronic devices that is compatible with roll-to-roll processing speeds exceeding 30 m/min.

Solution Processed Metal Oxide Thin Films for Electronic Applications discusses the fundamentals of solution processing materials chemistry techniques as they are applied to metal oxide materials systems for key device applications. The book introduces basic information (materials properties, materials synthesis, barriers), discusses ink formulation and solution processing methods, including sol-gel processing, surface functionalization aspects, and presents a comprehensive accounting on the electronic applications of solution processed metal oxide films, including thin film transistors, photovoltaic cells and other electronics devices and circuits. This is an important reference for those interested in oxide electronics, printed electronics, flexible electronics and large-area electronics. Provides in-depth information on solution processing fundamentals, techniques, considerations and barriers combined with key device applications Reviews important device applications, including transistors, light-emitting diodes, and photovoltaic cells Includes an overview of metal oxide materials systems (semiconductors, nanomaterials and thin films), addressing materials synthesis, properties, limitations and surface aspects

This book provides a comprehensive overview of the science of nanostructured oxides. It details the fundamental techniques and methodologies involved in oxides thin film and bulk growth, characterization and device processing, as well as heterostructures. Both, experts in oxide nanostructures and experts in thin film heteroepitaxy, contribute the interactions described within this book.

The Future of Semiconductor Oxides in Next-Generation Solar Cells begins with several chapters covering the synthesis of semiconductor oxides for NGSCs. Part II goes on to cover the types and applications of NGSCs currently under development, while Part III brings the two together, covering specific processing techniques for NGSC construction. Finally, Part IV discusses the stability of SO solar cells compared to organic solar cells, and the possibilities offered by hybrid technologies. This comprehensive book is an essential reference for all those academics and professionals who require thorough knowledge of recent and future developments in the role of semiconductor oxides in next generation solar cells. Unlocks the potential of advanced semiconductor oxides to transform Next Generation Solar Cell (NGSC) design Full coverage of new developments and recent research make this essential reading for researchers and engineers alike Explains the synthesis and processing of semiconductor oxides with a view to their use in NGSCs

With an in-depth exploration of the following topics, this book covers the broad uses of zinc oxide within the fields of materials science and engineering: - Recent advances in bulk , thin film and nanowire growth of ZnO (including MBE, MOCVD and PLD), - The characterization of the resulting material (including the related ternary systems ZgMgO and ZnCdO), - Improvements in device processing modules (including ion implantation for doping and isolation ,Ohmic and Schottky contacts , wet and dry etching), - The role of impurities and defects on materials properties - Applications of ZnO in UV light emitters/detectors, gas, biological and chemical-sensing, transparent electronics, spintronics and thin film

This is the first text to cover all aspects of solution processed functional oxide thin-films. Chemical Solution Deposition (CSD) comprises all solution based thin- film deposition techniques, which involve chemical reactions of precursors during the formation of the oxide films, i. e. sol-gel type routes, metallo-organic decomposition routes, hybrid routes, etc. While the development of sol-gel type processes for optical coatings on glass by silicon dioxide and titanium dioxide dates from the mid-20th century, the first CSD derived electronic oxide thin films, such as lead zirconate titanate, were prepared in the 1980’s. Since then CSD has emerged as a highly flexible and cost-effective technique for the fabrication of a very wide variety of functional oxide thin films. Application areas include, for example, integrated dielectric capacitors, ferroelectric random access memories, pyroelectric infrared detectors, piezoelectric micro-electromechanical systems, antireflective coatings, optical filters, conducting-, transparent conducting-, and superconducting layers, luminescent coatings, gas sensors, thin film solid-oxide fuel cells, and photoelectrocatalytic solar cells. In the appendix detailed “cooking recipes” for selected material systems are offered.

Oxides form a broad subject area of research and technology development which encompasses different disciplines such as materials science, solid state chemistry, physics etc. The aim of this book is to demonstrate the interplay of these fields and to provide an introduction to the techniques and methodologies involving film growth, characterization and device processing. The literature in this field is thus fairly scattered in different research journals covering one or the other aspect of the specific activity. This situation calls for a book that will consolidate this information and thus enable a beginner as well as an expert to get an overall perspective of the field, its foundations, and its projected progress.

Thin films have an extremely broad range of applications from electronics and optics to new materials and devices. Collaborative and multidisciplinary efforts from physicists, materials scientists, engineers and others have established and advanced a field with key pillars constituting (i) the synthesis and processing of thin films, (ii) the understanding of physical properties in relation to the nanometer scale, (iii) the design and fabrication of nano-devices or devices with thin film materials as building blocks, and (iv) the design and construction of novel tools for characterization of thin films.Against the backdrop of the increasingly interdisciplinary field, this book sets off to inform the basics of thin film physics and thin film devices. Readers are systematically introduced to the synthesis, processing and application of thin films; they will also study the formation of thin films, their structure and defects, and their various properties — mechanical, electrical, semiconducting, magnetic, and superconducting. With a primary focus on inorganic thin film materials, the book also ventures on organic materials such as self-assembled monolayers and Langmuir-Blodgett films.This book will be effective as a teaching or reference material in the various disciplines, ranging from Materials Science and Engineering, Electronic Science and Engineering, Electronic Materials and Components, Semiconductor Physics and Devices, to Applied Physics and more. The original Chinese publication has been instrumental in this purpose across many Chinese universities and colleges.

This publication provides an excellent one-stop resource for understanding the most important current issues in the research in processing, properties and applications in glass and optical materials.