Download or read book Investigation of the Optical and Electrical Properties of ZnO based Thin Films Grown Via Sol gel Method for Thin film Transistor Application written by 蘇泊沅 and published by . This book was released on 2013 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Investigations of the Properties of ZnO based TCO Thin Films Grown Via Rf Sputtering Deposition Method on Flexible Substrates for Thin film Transistor Applications written by 吳佳玲 and published by . This book was released on 2014 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sol Gel Spin Coating Growth Of Gallium Nitride Thin Films A Simple Safe and Cheap Approach Penerbit USM written by Fong Chee Yong and published by Penerbit USM. This book was released on 2019 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wide direct band gap gallium nitride (GaN) semiconductor has received significant attention as an ideal material for various applications in the optoelectronic devices. One major use of GaN is the development of energy-efficient solid state light-emitting diodes. Currently, most commercially available GaN semiconductor are produced through advanced deposition techniques which involve sophisticated technologies and are relatively expensive and complicated to setup. As an alternative, the sol-gel spin coating method, which is relatively simpler, cheaper, safer, and more scalable was proposed. In this book, the process route and recipe for producing highly c-oriented crystalline GaN thin films via the sol-gel spin coating approach were described in detail. Some insights into the factors affecting the surface morphology as well as structural and optical properties of the deposited films were presented. Eventually, this book could inspire further studies into the development of low-cost GaN thin films.

Download or read book Optimization of the Process for Sol gel Derived ZnO written by Matthew Nagorski and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Transparent and conducting Al-doped ZnO thin films with c-axis-preferred orientation were prepared on glass substrate via sol-gel route. The physical, optical and electrical properties were investigated to determine an optimal withdrawal speed, aluminum source and treatment in order to obtain a smooth, dense, highly crystalline, conductive and transparent thin film with a high figure of merit for transparent conducting oxide applications. An optimal withdrawal speed was found to be 2.5 cm/min. Optimal aluminum source and concentration was found to be 0.5 at.% using aluminum chloride hexahydrate. An additional treatment in an N2 environment was found to be the best method to improve the electrical properties of the films while maintaining high crystallinity and transparency.

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 Investigation of the Optical and Electrical Properties of ZnO based Transparent Conducting Thin Films on Flexible Substrates written by 蔡宜君 and published by . This book was released on 2011 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oxide and Nitride Semiconductors written by Takafumi Yao and published by Springer Science & Business Media. This book was released on 2009-03-20 with total page 525 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a unique book devoted to the important class of both oxide and nitride semiconductors. It covers processing, properties and applications of ZnO and GaN. The aim of this book is to provide the fundamental and technological issues for both ZnO and GaN.

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 ZnO Thin Films for Optoelectronic Applications written by Prasada Rao Talakonda and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) thin films have good electro-optical properties suitable for opto-electronic applications. The present study explains the deposition and characterization of n-type and p-type ZnO thin films by spray pyrolysis. The films were characterized by different methods to understand their structural, optical and electrical properties. Gallium was chosen as the impurity dopant in ZnO films to improve the electrical properties. The electrical conductivity, carrier concentration and mobility of Ga doped ZnO (GZO) films were highly improved in comparison to undoped ZnO films. The GZO films showed good optical transmittance in the visible region. The electrical and optical results suggest that the GZO films are suitable to use as a TCO in optoelectronic industries. The p-type ZnO thin films were successesfully realized using dual acceptor method. The Hall measurements and room temperature photolumiscence results were supported p-type nature of (Li, N): ZnO thin films.

Download or read book SYNTHESIS AND CHARACTERIZATION OF TRANSPARENT CONDUCTIVE ZINC OXIDE THIN FILMS BY SOL GEL SPIN COATING METHOD written by David Winarski and published by . This book was released on 2015 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide has been given much attention recently as it is promising for various semiconductor device applications. ZnO has a direct band gap of 3.3 eV, high exciton binding energy of 60 meV and can exist in various bulk powder and thin film forms for different applications. ZnO is naturally n-type with various structural defects, which sparks further investigation into the material properties. Although there are many potential applications for this ZnO, an overall lack of understand and control of intrinsic defects has proven difficult to obtain consistent, repeatable results. This work studies both synthesis and characterization of zinc oxide in an effort to produce high quality transparent conductive oxides. The sol-gel spin coating method was used to obtain highly transparent ZnO thin films with high UV absorbance. This research develops a new more consistent method for synthesis of these thin films, providing insight for maintaining quality control for each step in the procedure. A sol-gel spin coating technique is optimized, yielding highly transparent polycrystalline ZnO thin films with tunable electrical properties. Annealing treatment in hydrogen and zinc atmospheres is researched in an effort to increase electrical conductivity and better understand intrinsic properties of the material. These treatment have shown significant effects on the properties of ZnO. Characterization of doped and undoped ZnO synthesized by the sol-gel spin coating method was carried out using scanning electron microscopy, UV-Visible range absorbance, X-ray diffraction, and the Hall Effect. Treatment in hydrogen shows an overall decrease in the number of crystal phases and visible absorbance while zinc seems to have the opposite effect. The Hall Effect has shown that both annealing environments increase the n-type conductivity, yielding a ZnO thin film with a carrier concentration as high as 3.001 × 1021 cm-3.

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 Optimisation of ZnO Thin Films written by Saurabh Nagar and published by Springer. This book was released on 2017-05-22 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph describes the different implantation mechanisms which can be used to achieve strong, reliable and stable p-type ZnO thin films. The results will prove useful in the field of optoelectronics in the UV region. This book will prove useful to research scholars and professionals working on doping and implantation of ZnO thin films and subsequently fabricating optoelectronic devices. The first chapter of the monograph emphasises the importance of ZnO in the field of optoelectronics for ultraviolet (UV) region and also discusses the material, electronic and optical properties of ZnO. The book then goes on to discuss the optimization of pulsed laser deposited (PLD) ZnO thin films in order to make successful p-type films. This can enable achievement of high optical output required for high-efficiency devices. The book also discusses a hydrogen implantation study on the optimized films to confirm whether the implantation leads to improvement in the optimized results.

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 Manipulation of Electrical Resistivity and Optical Properties of Zinc Oxide Thin Films Grown by Pulsed Laser Deposition and the Sol Gel Method written by Ryan W. Crisp and published by . This book was released on 2012 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel Synthesis and Fabrication of ZnO Thin Films Via an Anhydrous Sol gel Route written by Lee Huat Kelly Koh and published by . This book was released on 2008 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, the aim to synthesise nano-sized zinc oxide particles in the form of thin films by using a novel anhydrous sol-gel technique was proposed, developed and demonstrated. The sol-gel was prepared using anhydrous zinc acetate [Zn(C2H3O2)2], monoethanolamine [H2NC2H4OH ] and isopropanol. The zinc oxide thin films were fabricated on soda-lime and fused silica substrates from both single- and multi- step spin-coating depositions. A range of widely reported zinc acetate concentrations, annealing temperatures and spin-coating speeds was chosen to characterise and study the various effects that these parameters have on the crystallographical, morphological, optical, electronic and electrical properties. The mean crystallite sizes and other structural properties (such as micro-strain and degree of crystallinity) were estimated using x-ray diffraction analysis. In combination with scanning electron microscopy, the increase in particle size was observed to be non-linear, changing from that of individual growth to that of particle conglomeration at higher precursor concentration and annealing temperature. Strong crystalline orientation along the (002) c-axis crystalline plane (with intensity ratio _ (002) value up to 0.95) was exhibited for films fabricated from low precursor concentrations, multi-layered and furnace pre-heated films. Optical transmittance and electronic bandgap was measured and calculated using UV-visible spectroscopy. Thin films with high transparency (> 98 % (T) after substrate subtraction) were achieved for films prepared from low precursor concentrations, while absorption wavelength and optical bandgap energy were consistent and in good agreement with recognised values of zinc oxide. Reproducibility and reliability tests carried out on the films show high morphological consistency and stability against temperature fluctuation, moisture and electrochemical effects. Surface morphologically, the films were dense. The electrical resistivity of the (single- and multi- layer) films, before and after forming gas treatment was also measured. The minimum resistivity value of all the single-layer films was calculated to be 9.58 x 102 _cm, and the electrical resistivity showed an overall mprovement (up to one order of magnitude). On contrary, the multi-layered films, which are more resistive, worsened in resistivity after forming gas treatment.

Download or read book Multifunctional Oxide Based Materials From Synthesis to Application written by Teofil Jesionowski and published by MDPI. This book was released on 2019-09-03 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book deals with novel aspects and perspectives in metal oxide and hybrid material fabrication. The contributions are mainly focused on the search for a new group of advanced materials with designed physicochemical properties, especially an expanded porous structure and defined surface activity. The proposed technological procedures result in an enhanced activity of the synthesized hybrid materials, which is of great importance when considering their potential fields of application. The use of such materials in different technological disciplines, including aspects associated with environmental protection, allows for the verification of the proposed synthesis method. Thus, it can be stated that those aspects are of interdisciplinary character and may be located at the interface of three scientific disciplines—chemistry, materials science, and engineering—as well as environmental protection. Furthermore, the presented scientific scope is in some way an answer to the continuous demand for such types of materials and opens new perspectives for their practical use