Download or read book Film Growth and Electrical Properties of Solution Processed Zinc Oxide in Thin Film Transistors written by Marlis Ortel and published by . This book was released on 2013 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: High performance TFTs showing excellent stability even in air were developed based on investigations describing physical and chemical mechanisms related to zinc oxide film growth and its electrical properties. Therefore the growth and nucleation of zinc oxide thin films deposited by pulsed spray pyrolysis utilizing non-toxic materials were correlated to the boiling curve and Leidenfrost effect of water which was employed as solvent. The optimized deposition parameters were utilized to fabricate ZnO-TFTs. Different growth conditions and their impact on trap state formation inside the bulk material were analyzed taking chemical purity and grain boundary models into account. Moreover it was distinguished between the contribution of surface and bulk trap state on the storage and gate bias stress stability in different atmospheres. Mainly surface states which are sensitive to humid atmosphere show significant impact on the electrical stability of TFTs. Hence different fluoro-terminated compounds which bind selective on active surface sites which are either related to Zn2+-ions or hydroxyl-groups were investigated. 4,4,4-Trifluoro-1-phenylbutane-1,3-dione which chalets to Zn2+-ions was found to be a suitable candidate to reduce the number of surface trap states significantly which leads to highly stable TFT performance and a strong increase in mobility. Since this approach has not been reported elsewhere yet a patent application was filed.

Download or read book Zinc Oxide Bulk Thin Films and Nanostructures written by Chennupati Jagadish and published by Elsevier. This book was released on 2011-10-10 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book ZnO Thin Film Transistors for Cost Efficient Flexible Electronics written by Fábio Fedrizzi Vidor and published by Springer. This book was released on 2017-12-28 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the integration, characterization and analysis of cost-efficient thin-film transistors (TFTs), applying zinc oxide as active semiconductors. The authors discuss soluble gate dielectrics, ZnO precursors, and dispersions containing nanostructures of the material, while different transistor configurations are analyzed with respect to their integration, compatibility, and device performance. Additionally, simple circuits (inverters and ring oscillators) and a complementary design employing (in)organic semiconducting materials are presented and discussed. Readers will benefit from concise information on cost-efficient materials and processes, applied in flexible and transparent electronic technology, such as the use of solution-based materials and dispersion containing nanostructures, as well as discussion of the physical fundamentals responsible for the operation of the thin-film transistors and the non-idealities of the device.

Download or read book Zinc Oxide Thin Film Transistors written by Divine Khan Ngwashi and published by LAP Lambert Academic Publishing. This book was released on 2011-05 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transparent oxide semiconducting films have continued to receive considerable attention, from a fundamental and application-based point of view, primarily because of their useful fundamental properties. Of particular interest is zinc oxide (ZnO), an n-type semiconductor that exhibits excellent optical, electrical, catalytic and gas-sensing properties, and has many applications in various fields. In this work, thin film transistor (TFT) arrays based on ZnO have been prepared by reactive radio frequency (RF) magnetron sputtering. The sputtering process was carried out at room temperature with no intentional heating. The aim of this is to prepare ZnO thin films with stable semiconducting electrical properties to be used as the active channel in TFTs; and to understand the role of intrinsic point defects in device performance and stability. The effect of oxygen (O2) adsorption on TFT device characteristics is also investigated. TFTs incorporating silicon dioxide, and different high-k dielectrics are also investigated.

Download or read book Transparent Electronics written by Elvira Fortunato and published by . This book was released on with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrical Properties of Zinc oxide based Thin film Transistors Using Strontium oxide doped Semiconductors Project Supported by the National Natural Science Foundation of China Grant No 6140031454 and the Innovation Program of Chinese Academy of Sciences and State Key Laboratory of Luminescence and Applications written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Strontium-zinc-oxide (SrZnO) films forming the semiconductor layers of thin-film transistors (TFTs) are deposited by using ion-assisted electron beam evaporation. Using strontium-oxide-doped semiconductors, the off-state current can be dramatically reduced by three orders of magnitude. This dramatic improvement is attributed to the incorporation of strontium, which suppresses carrier generation, thereby improving the TFT. Additionally, the presence of strontium inhibits the formation of zinc oxide (ZnO) with the hexagonal wurtzite phase and permits the formation of an unusual phase of ZnO, thus significantly changing the surface morphology of ZnO and effectively reducing the trap density of the channel.

Download or read book Zinc Oxide written by Hadis Morkoç and published by John Wiley & Sons. This book was released on 2008-12-03 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first systematic, authoritative and thorough treatment in one comprehensive volume presents the fundamentals and technologies of the topic, elucidating all aspects of ZnO materials and devices. Following an introduction, the authors look at the general properties of ZnO, as well as its growth, optical processes, doping and ZnO-based dilute magnetic semiconductors. Concluding sections treat bandgap engineering, processing and ZnO nanostructures and nanodevices. Of interest to device engineers, physicists, and semiconductor and solid state scientists in general.

Download or read book Design Simulation and Construction of Field Effect Transistors written by Dhanasekaran Vikraman and published by BoD – Books on Demand. This book was released on 2018-07-18 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, research on microelectronics has been specifically focused on the proposition of efficient alternative methodologies and materials to fabricate feasible integrated circuits. This book provides a general background of thin film transistors and their simulations and constructions. The contents of the book are broadly classified into two topics: design and simulation of FETs and construction of FETs. All the authors anticipate that the provided chapters will act as a single source of reference for the design, simulation and construction of FETs. This edited book will help microelectronics researchers with their endeavors and would be a great addition to the realm of semiconductor physics.

Download or read book Les Enfants d Edouard written by and published by . This book was released on 1909 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Zinc Oxide A Material for Micro and Optoelectronic Applications written by Norbert H. Nickel and published by Springer Science & Business Media. This book was released on 2005-12-28 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, a significant effort has been devoted to the investigation of ZnO as a suitable semiconductor for UV light-emitting diodes, lasers, and detectors and hetero-substrates for GaN. Research is driven not only by the technological requirements of state-of-the-art applications but also by the lack of a fundamental understanding of growth processes, the role of intrinsic defects and dopants, and the properties of hydrogen. The NATO Advanced Research Workshop on “Zinc oxide as a material for micro- and optoelectronic applications”, held from June 23 to June 25 2004 in St. Petersburg, Russia, was organized accordingly and started with the growth of ZnO. A variety of growth methods for bulk and layer growth were discussed. These techniques comprised growth methods such as closed space vapor transport (CSVT), metal-organic chemical vapor deposition, reactive ion sputtering, and pulsed laser deposition. From a structural point of view using these growth techniques ZnO can be fabricated ranging from single crystalline bulk material to polycrystalline ZnO and nanowhiskers. A major aspect of the ZnO growth is doping. n-type doping is relatively easy to accomplish with elements such al Al or Ga. At room temperature single crystal ZnO exhibits a resistivity of about 0. 3 -cm, an electron mobility of 2 17 -3 225 cm /Vs, and a carrier concentration of 10 cm . In n-type ZnO two shallow donors are observable with activation energies of 30 – 40 meV and 60 – 70 meV.

Download or read book ZnO Thin Films written by Paolo Mele and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) is an n-type semiconductor with versatile applications such as optical devices in ultraviolet region, piezoelectric transducers, transparent electrode for solar cells and gas sensors. This book "ZnO Thin Films: Properties, Performance and Applications" gives a deep insight in the intriguing science of zinc oxide thin films. It is devoted to cover the most recent advances and reviews the state of the art of ZnO thin films applications involving energy harvesting, microelectronics, magnetic devices, photocatalysis, photovoltaics, optics, thermoelectricity, piezoelectricity, electrochemistry, temperature sensing. It serves as a fundamental information source on the techniques and methodologies involved in zinc oxide thin films growth, characterization, post-deposition plasma treatments and device processing. This book will be invaluable to the experts to consolidate their knowledge and provide insight and inspiration to beginners wishing to learn about zinc oxide thin films.

Download or read book Electrical Characterization of ZnO thin films grown by molecular beam epitaxy written by Vladimir Petukhov and published by Cuvillier Verlag. This book was released on 2012-04-25 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the electronic and optoelectronic device realization a precise control of the electrical properties in the utilized material is a very important issue. Doping profiles in realized p-njunctions influence the functionality of the devices. The morphological and crystal properties of a device material directly influence the electrical ones. Dislocations present in a region of p-n-junctions can short circuit them leading to malfunctions. Too rough surfaces during epitaxial growth could lead to inhomogeneities in a single or multiple quantum wells and superlattices. The main goal of the present work was to provide the basis for a reliable p-type doping of ZnO grown by molecular beam epitaxy. Firstly, the well established heteroepitaxial growth on c-sapphire substrates has been employed. Based on the theoretical and experimental works, suggesting nitrogen to be the impurity that builds the most shallow acceptor level in ZnO comparing to other group-V elements, it has been implied as a dopant. To generate reactive nitrogen atoms an rf-plasma source has been utilized in the MBE process. The resulting samples have been characterized by such methods as AFM, XRD, TEM, PL spectroscopy, temperature domain Hall measurements (TDHM) and ECV-profiling. First results of TDHM have shown that even in undoped samples the temperature dependencies of the electron mobility and carrier concentration have regions which are difficult to interpret. It is necessary to fit them with theoretical curves in order to extract the correct values. This task has proven to be very difficult. The complicated character of the dependencies has been explained in terms of the multilayer conduction model dividing a layer in thin interfacial region with mobility and carrier concentration μ1 and n1 respectivly and bulk region with a higher mobility μ2 and lower carrier concentration n2. The electrical transport in the bulk region has been modeled in terms of the general scattering theory in polar semiconductors. Such scattering mechanisms as scattering on polar-optical phonons, piezoelectric phonons, acoustic deformation potential, strain induced fields, dislocations, ionized and neutral impurities have been taken into account. Two cases have been considered to model transport in the interfacial region: 1) transport takes place in the conduction band of a highly doped degenerate semiconductor; 2) transport takes place in the impurity band formed by intermediate concentration of impurities and in conduction band in parallel. In the second case transport at the interface in conduction band has been neglected in the region of the low temperatures due to the impurities freeze-out and carrier concentration has been taken temperature independent like in the first case. To investigate experimentally the transport character in these two regions independently a mobility-spectrum analysis has been conducted. Theoretical results utilizing the two models have been compared with experimentally extracted mobility and carrier concentration in the interfacial region. It has been concluded that the concentration of donors in the layers is not high enough for the impurity band to merge with the conduction band and the second model is more consistent. The theoretically acquired donor concentration profiles have been compared with ECV-profiles. The agreement is very good. Simulations have revealed a shallow donor state with the ionization energy of approximately 45 meV . In the literature, this donor state in ZnO is attributed to hydrogen. However, due to the high diffusion mobility of hydrogen in ZnO, an annealing process would obviously decrease the carrier concentration in the samples which has not been the case. It has been suggested that the main donor centers are the electrically active crystal point defects generated by dislocations. Layers doped with nitrogen have been grown at very low temperatures (≈ 200°C) and at temperatures ranging from 400°C to 500°C, which are optimal for the epitaxial growth of ZnO. The samples grown at low temperatures are single crystalline with mosaic structure. In both cases, the introduction of the dopant increased the carrier concentration. This has been accounted for a bad crystal quality resulting in the inhomogeneous incorporation of nitrogen and for high background donor concentration due to the high dislocations densities. Additionally, the incorporation of acceptor centers shifts the Fermi-level increasing the formation probability of the compensating point defects. The analysis of TDHM showed an inconsistency of the one donor level model in the case of nitrogen doped samples. This fact and the decrease in the carrier concentration after annealing at 800°C for 30 minutes in ambient air can be explained by nitrogen forming donor-like defect complexes. In an attempt to improve the crystal quality of the heteroepitaxial layers, 15 periods of a ZnO/Zn0.6Mg0.4O superlattice structure have been inserted between the conventional double HT-MgO/LT-ZnO buffer and a main HT-ZnO layer. TDHM has revealed a very high mobility close to the values measured in a bulk ZnO for the temperature range of 20 - 300 K. However, TEM investigations of the samples have not indicated any decrease in the dislocation density comparing with the similar samples without a superlattice. Such a high mobility has been attributed to an electron transport in the superlattice structure. Heteroepitaxial growth of high quality ZnO-layers has proven to be challenging leaving the homoepitaxial growth as the only possibility to obtain the epitaxial layers with the best structural and electrical properties. The hydrothermally grown bulk ZnO substrates from two supplying companies, CrysTec and TokyoDenpa, have been employed for homoepitaxy. The substrates from CrysTec have not been epi-ready. Although AFM images reveal very flat surface, this has been damaged by the process of the chemomechanical polishing. This damaged layer must be removed. This has been achieved by the thermal annealing for 3 hours at 1050°C in ambient air. The thermally treated surfaces resulted in atomically flat terraces. XRD measurements have indicated an improvement of the crystal quality after annealing. The resistivity of the bulk substrates decreased after the thermal treatment due to out-diffusion of the compensating Li atoms letting Al, Ga and In atoms to contribute to conduction. After the longer annealing processes the etch-pits have been discovered on O-polar faces. The same features could be achieved by the chemical etching in a nitric acid on Zn-polar faces. The density of the threading dislocations on both polar faces for both types of substrates calculated by the etch-pit density investigation is about 105 1/cm2. Further the thermally treated substrates with atomically flat terraces have been utilized for homoepitaxy. The differences in growth kinetics during the molecular beam epitaxy on such substrates with the improved surface quality depending on their polarity have been investigated by RHEED measurements. The growth on a Zn-polar face has a 3D-character independently on a supplier. Morphologies of the resulting O- and Zn-polar layers have shown to be different. This has been explained by the presence of dangling bonds on Opolar face and thus, shorter diffusion time of the impinging Zn atoms on the surface. XRD and TEM measurements have shown a perfect crystal quality of the overgrown layers. The PL spectra of homoepitaxial layers are governed by the donor impurities diffused from the substrates. Considering the SIMS measurements of homoepitaxial layers found in the literature it has been concluded that the diffusion of donors in the layers grown on Zn-polar faces takes less effect then for the O-polar films. This conclusion has enforced the utilization of Zn-polar substrates supplied by CrysTec for the experiments with nitrogen doping of ZnO because of their affordable price. The electrical properties measured by ECV-profiling in series of homoepitaxial layers with varied growth parameters have shown an increase of the carrier concentration with the nitrogen incorporation. In addition, it has also been shown that the resulting electrical properties near the interface are governed mostly by the initial properties of the substrates. With increasing thickness of the layers carrier concentration saturated to the values of around 1016 1/cm3. The recent successful realization of the p-type MgZnO layers on TokyoDenpa substrates by researchers from Japan suggests switching to the p-type doped alloys because the above discussed results indicate that p-type doping with nitrogen of a pure ZnO is very difficult or even impossible. This is due to a rather fundamental reason: the formation of the compensating donor centers with the incorporation of acceptor atoms. As the first step in the future works, it is obvious to try to reproduce the results of the ZnMgO p-type doping with nitrogen employing growth on ZnO substrates.

Download or read book Solution Processed Zinc Oxide Thin film Transistors written by Hendrik Andreas Faber and published by . This book was released on 2012 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of the Performance and Stability of Zinc Oxide Thin film Transistors and the Role of High k Dielectrics written by Ngwashi Divine Khan and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Transparent oxide semiconducting films have continued to receive considerable attention, from a fundamental and application-based point of view, primarily because of their useful fundamental properties. Of particular interest is zinc oxide (ZnO), an n-type semiconductor that exhibits excellent optical, electrical, catalytic and gas-sensing properties, and has many applications in various fields. In this work, thin film transistor (TFT) arrays based on ZnO have been prepared by reactive radio frequency (RF) magnetron sputtering. Prior to the TFT fabrication, ZnO layers were sputtered on to glass and silicon substrates, and the deposition parameters optimised for electrical resistivities suitable for TFT applications. The sputtering process was carried out at room temperature with no intentional heating. The aim of this work is to prepare ZnO thin films with stable semiconducting electrical properties to be used as the active channel in TFTs; and to understand the role of intrinsic point defects in device performance and stability. The effect of oxygen (O2) adsorption on TFT device characteristics is also investigated. The structural quality of the material (defect type and concentration), electrical and optical properties (transmission/absorption) of semiconductor materials are usually closely correlated. Using the Vienna ab-initio simulation package (VASP), it is predicted that O2 adsorption may influence film transport properties only within a few atomic layers beneath the adsorption site. These findings were exploited to deposit thin films that are relatively stable in atmospheric ambient with improved TFT applications. TFTs incorporating the optimised layer were fabricated and demonstrated very impressive performance metrics, with effective channel mobilities as high as 30 cm2/V-1s-1, on-off current ratios of 107 and sub-threshold slopes of 0.9? 3.2 V/dec. These were found to be dependent on film thickness (~15? 60 nm) and the underlying dielectric (silicon dioxide (SiO2), gadolinium oxide (Gd2O3), yttrium oxide (Y2O3) and hafnium oxide (HfO2)). In this work, prior to sputtering the ZnO layer (using a ZnO target of 99.999 % purity), the sputtering chamber was evacuated to a base pressure ~4 x 10-6 Torr. Oxygen (O2) and argon (Ar) gas (with O2/Ar ratio of varying proportions) were then pumped into the chamber and the deposition process optimised by varying the RF power between 25 and 500 W and the O2/Ar ratio between 0.010 to 0.375. A two-level factorial design technique was implemented to test specific parameter combinations (i.e. RF power and O2/Ar ratio) and then statistical analysis was utilised to map out the responses. The ZnO films were sputtered on glass and silicon substrates for transparency and resistivity measurements, and TFT fabrication respectively. For TFT device fabrication, ZnO films were deposited onto thermally-grown silicon dioxide (SiO2) or a high-k dielectric layer (HfO2, Gd2O3 and Y2O3) deposited by a metal-organic chemical deposition (MOCVD) process. Also, by using ab initio simulation as implemented in the?Vienna ab initio simulation package (VASP)?, the role of oxygen adsorption on the electrical stability of ZnO thin film is also investigated. The results indicate that O2 adsorption on ZnO layers could modify both the electronic density of states in the vicinity of the Fermi level and the band gap of the film. This study is complemented by studying the effects of low temperature annealing in air on the properties of ZnO films. It is speculated that O2 adsorption/desorption at low temperatures (150? 350 0C) induces variations in the electrical resistance, band gap and Urbach energy of the film, consistent with the trends predicted from DFT results.

Download or read book Functional Oxide Based Thin Film Materials written by Dong-Sing Wuu and published by MDPI. This book was released on 2020-05-29 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Special Issue on Functional Oxide-Based Thin-Film Materials touches on the latest advancements in several aspects related to material science: the synthesis of novel oxide, photoluminescence characteristics, photocatalytic ability, energy storage, light emitter studies, low-emissivity glass coatings, and investigations of both nanostructure and thin-film properties. It represents an amalgamation of specialists working with device applications and shedding light on the properties and behavior of thin-film oxides (e.g., GaOx, Ga2O3, HfO2, LiNbO3, and doped ZnO, among numerous others). The papers cover many aspects of thin-film science and technology, from thin film to nanostructure and from material properties to optoelectronic applications, thus reflecting the many interests of the community of scientists active in the field.

Download or read book Recent Applications in Sol Gel Synthesis written by Usha Chandra and published by BoD – Books on Demand. This book was released on 2017-07-05 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Versatility, extended compositional ranges, better homogeneity, lesser energy consumption, and requirement of nonexpensive equipments have boosted the use of sol-gel process on top of the popularity in the synthesis of nanosystems. The sol-gel technique has not only revolutionized oxide ceramics industry and/or material science but has also extended widely into multidimensional applications. The book Recent Applications in Sol-Gel Synthesis comprises 14 chapters that deal mainly with the application-oriented aspects of the technique. Sol-gel prepared metal oxide (MO) nanostructures like nanospheres, nanorods, nanoflakes, nanotubes, and nanoribbons have been employed in biomedical applications involving drug deliveries, mimicking of natural bone, and antimicrobial activities. The possibility of controlling grain size in aerogel and preparation of ultrahigh-temperature ceramic (UHTC)-based materials, fluorescent glasses, ultraviolet photosensors, and photocatalysts have been discussed in detail by the experts in the field. The usefulness of sol-gel materials as active GRIN, as textile finisher, and as leather modifier with water-repellent and oil-resistive properties would be an incentive for researchers keen to pursue the field.

Download or read book Optimization on the Electrical Performance of the Solution Processed Zinc Tin Oxide Thin film Transistors and Its Application Research for Artificial Synapses written by Tianshi Zhao and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: