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Articoli di riviste sul tema "Metal oxydes and transparent conducting materials"
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Kim, Yujin, Sung Hwan Joo, Seong Gwan Shin, Hyung Wook Choi, Chung Wung Bark, You Seung Rim, Kyung Hwan Kim e Sangmo Kim. "Effect of Annealing in ITO Film Prepared at Various Argon-and-Oxygen-Mixture Ratios via Facing-Target Sputtering for Transparent Electrode of Perovskite Solar Cells". Coatings 12, n. 2 (4 febbraio 2022): 203. http://dx.doi.org/10.3390/coatings12020203.
Testo completoAbstract (sommario):
Normal perovskite solar cells (PSCs) consist of the following layers: transparent electrode, electron-transport layer (ETL), light-absorbing perovskite layer, hole-transport layer (HTL), and metal electrode. Energy, such as electricity, is produced through light absorbance and electron–hole generation/transport between two electrode types (metal film and transparent conducting film). Among stacked layers in a PSC, the transparent electrode plays the high-performance-power-conversion-efficiency role. Transparent electrodes should have high-visible-range transparency and low resistance. Therefore, in this study, we prepared indium tin oxide (ITO) films on a glass substrate by using facing-target sputtering without substrate heating treatment and investigate the heating-treatment effect on the ITO-film properties for perovskite solar cells (PSCs). Moreover, we fabricated PSCs with ITO films prepared at various oxygen flows during the sputtering process, and their energy-conversion properties are investigated.
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Major, S., M. C. Bhatnagar, S. Kumar e K. L. Chopra. "The effect of hydrogen plasma on the properties of indium-tin oxide films". Journal of Materials Research 3, n. 4 (agosto 1988): 723–28. http://dx.doi.org/10.1557/jmr.1988.0723.
Testo completoAbstract (sommario):
The effect of hydrogen plasma exposure on the properties of transparent conducting indium-tin oxide films has been studied. The exposure reduces the film surface to elemental indium. The thickness of the reduced layer increases with increasing exposure and finally saturates to a thickness of about 100 nm. The reduced surface is rough and decreases the visible transmittance of these films drastically due to increased absorptance and reflectance. The reduced metal layer decreases the sheet resistance of the films. Annealing of the plasma-exposed film in oxygen recovers the visible transmittance except in the case of the severely damaged films.
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Rouviller, Axel, Aline Jolivet, Alex Misiak, Moussa Mezhoud, Christophe Labbé, Julien Cardin, Xavier Portier et al. "Structural, Electrical and Optical Properties of Zn-Doped SrVO3 Thin Films Grown By Co-Sputtering". ECS Meeting Abstracts MA2023-02, n. 34 (22 dicembre 2023): 1669. http://dx.doi.org/10.1149/ma2023-02341669mtgabs.
Testo completoAbstract (sommario):
Due to its optical and electrical characteristics, SrVO3 is a strongly correlated metal that has received extensive research in recent years. This makes it a promising transparent conducting oxide (TCO) for a variety of optoelectronic applications. The most widely used TCO at the moment, indium tin oxide, suffers from resource depletion. By analyzing and improving these interesting properties, SrVO3 might be able to take its place [1]. Unfortunately, in order to obtain SrVO3 as a crystallized phase, non-compatible with microelectronic industry thin film growth techniques must be used. Moreover, they require specific substrates for achieving the crystalline state, such as SrTiO3, LaAlO3, and (LaAlO3)0,3(Sr2TaAlO6)0,7 (LSAT) [2]. Nevertheless, recent studies made by our groups have demonstrated that crystalline SrVO3 layers may be produced on less expensive substrates such as glass or silicon substrates, with the simple use of a TiO2 buffer layer. This recent finding is covered by a global patent [3]. In the present work, we report experimental investigations on the reactively co-sputtering of SrVO3 and ZnO targets in a H-rich plasma, on Si substrates, with and without a TiO2 buffer layer, to grow transparent and conductive films. TiO2 buffer layer has been deposited on Si Substrate by Atomic Layer Deposition as reported elsewhere [4]. We looked at the effects of growth temperatures (TG) and the hydrogen rate rH (the ratio of H2 to Ar) on the thin films’ structural, electrical, and optical characteristics. XRD, high-resolution TEM, and AFM techniques were used to examine the films’ structural characteristics. The 4 probes approach, Van der Pauw measurements using a PPMS, and Hall effect measurements were used to examine the electrical properties. Finally, spectroscopic ellipsometry was used to conduct optical characterizations. The structural analysis showed that it is possible to favor the growth of crystalline SrVO3 layers on top of the TiO2 buffer layer by optimizing TG and rH (Figure 1a). In some specific conditions, a partially crystallized layer of SrVO3 was also directly deposited on a Si substrate without the use of such a buffer layer, which has never been reported in the literature and thus is encouraging for the future growth of such material on-low-cost substrate (Figure 1b). The Zn concentration in the film is only 0.15 at% because the radio-frequency (RF) power density applied to the ZnO target is much lower than the one applied to the SrVO3 target. The presence of dopants during the development process may favor the crystallization of SrVO3, which may help to explain this partial crystallization. This finding might pave the way for buffer-free complete crystallization of SrVO3 on Si substrates. When the films are grown on a TiO2 buffer layer, measurements of the physical properties have evidenced that it is possible to form thin films with optical transparency ranging from 70 to 75%, between 475 and 800 nm (Figure 1c). The thin films’ electrical resistivities at ambient temperature reach values of 1.2 × 10−3 Ohm.cm, according to electrical characterizations performed on them using the 4 probes method. Moreover, the PPMS data reveal a decrease in resistivity as a function of temperature (Figure 1d) which is the signature of semiconductor behavior. Such a feature has never been reported elsewhere and is probably due to an excess of oxygen in the layer induced 2 by the reactive growth approach. The vanadate films detailed in this paper present a sufficiently low resistivity to be used for microelectronics applications since the films produced with optimal values of rH and TG are more conductive than the undoped semiconductor films typically used as TCOs, such as ZnO and SnO2. In addition, these films feature an optical band gap, and therefore offer the opportunity to create materials with photoluminescence properties by doping them with rare earth ions for example. This is extremely promising for the design of light-emitting diodes or sensors. [1] L. Zhang et al, “Correlated metals as transparent conductors,” Nature materials, vol. 15,12 2015. [2] A. Boileau et al, “Tuning of the optical properties of the transparent conducting oxide SrVO3 by electronic correlations,” Advanced Optical Materials, vol. 7, p. 1801516, 01 2019. [3] Patent FR3113185 [4] A. Jolivet et al, “Structural, optical, and electrical properties of TiO2 thin films deposited by ALD: Impact of the substrate, the deposited thickness and the deposition temperature,” Applied Surface Science, vol. 608, p. 155214, 2023. Figure 1
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Ginley, David S., e Clark Bright. "Transparent Conducting Oxides". MRS Bulletin 25, n. 8 (agosto 2000): 15–18. http://dx.doi.org/10.1557/mrs2000.256.
Testo completoAbstract (sommario):
In the interim between the conception of this issue of MRS Bulletin on transparent conducting oxides (TCOs) and its publication, the remarkable applications dependent on these materials have continued to make sweeping strides. These include the advent of larger flat-screen high-definition televisions (HDTVs), larger and higher-resolution screens on portable computers, the increasing importance of low emissivity (“low-e”) and electrochromic windows, a significant increase in the manufacturing of thin-film photovoltaics (PV), and a plethora of new hand-held and smart devices, all with smart displays.1-7 Coupled with the increased importance of TCO materials to these application technologies has been a renaissance over the last two years in the science of these materials. This has included new n-type materials, the synthesis of true p-type materials, and the theoretical prediction and subsequent confirmation of the applicability of codoping to produce p-type ZnO. Considering that over the last 20 years much of the work on TCOs was empirical and focused on ZnO and variants of InxSn1-xO2, it is quite remarkable how this field has exploded. This may be a function of not only the need to achieve higher performance levels for these devices, but also of the increasing importance of transition-metal-based oxides in electro-optical devices. This issue of MRS Bulletin is thus well timed to provide an overview of this rapidly expanding area. Included are articles that cover the industrial perspective, new n-type materials, new p-type materials, novel deposition methods, and approaches to developing both an improved basic understanding of the materials themselves as well as models capable of predicting performance limits.
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Elbahri, Mady, Mehdi Keshavarz Hedayati, Venkata Sai Kiran Chakravadhanula, Mohammad Jamali, Thomas Strunkus, Vladimir Zaporojtchenko e Franz Faupel. "An Omnidirectional Transparent Conducting-Metal-Based Plasmonic Nanocomposite". Advanced Materials 23, n. 17 (28 marzo 2011): 1993–97. http://dx.doi.org/10.1002/adma.201003811.
Testo completo
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Budianu, E., M. Purica, F. Iacomi, C. Baban, P. Prepelita e E. Manea. "Silicon metal-semiconductor–metal photodetector with zinc oxide transparent conducting electrodes". Thin Solid Films 516, n. 7 (febbraio 2008): 1629–33. http://dx.doi.org/10.1016/j.tsf.2007.07.196.
Testo completo
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Hoshino, Katsuyoshi, Naoki Yazawa, Yoshiyasu Tanaka, Takeshi Chiba, Takenori Izumizawa e Minako Kubo. "Polycarbazole Nanocomposites with Conducting Metal Oxides for Transparent Electrode Applications". ACS Applied Materials & Interfaces 2, n. 2 (2 febbraio 2010): 413–24. http://dx.doi.org/10.1021/am900684e.
Testo completo
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Yang, Jie, Chunxiong Bao, Kai Zhu, Tao Yu e Qingyu Xu. "High-Performance Transparent Conducting Metal Network Electrodes for Perovksite Photodetectors". ACS Applied Materials & Interfaces 10, n. 2 (5 gennaio 2018): 1996–2003. http://dx.doi.org/10.1021/acsami.7b15205.
Testo completo
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Sepat, Neha, Vikas Sharma, Devendra Singh, Garima Makhija e Kanupriya Sachdev. "Nature-inspired bilayer metal mesh for transparent conducting electrode application". Materials Letters 232 (dicembre 2018): 95–98. http://dx.doi.org/10.1016/j.matlet.2018.08.088.
Testo completo
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Maurya, Sandeep Kumar, Hazel Rose Galvan, Gaurav Gautam e Xiaojie Xu. "Recent Progress in Transparent Conductive Materials for Photovoltaics". Energies 15, n. 22 (19 novembre 2022): 8698. http://dx.doi.org/10.3390/en15228698.
Testo completoAbstract (sommario):
Transparent conducting materials (TCMs) are essential components for a variety of optoelectronic devices, such as photovoltaics, displays and touch screens. In recent years, extensive efforts have been made to develop TCMs with both high electrical conductivity and optical transmittance. Based on material types, they can be mainly categorized into the following classes: metal oxides, metal nanowire networks, carbon-material-based TCMs (graphene and carbon nanotube networks) and conjugated conductive polymers (PEDOT:PSS). This review will discuss the fundamental electrical and optical properties, typical fabrication methods and the applications in solar cells for each class of TCMs and highlight the current challenges and potential future research directions.
Tesi sul tema "Metal oxydes and transparent conducting materials"
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Mohgouk, Zouknak Louis David. "Optimisation d'oxydes métalliques pour la réalisation d’électrode en adéquation avec le matériau photosensible dans l'infrarouge". Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALT031.
Testo completoAbstract (sommario):
Au cours des dernières décennies, le développement de matériaux à zéro dimension (0D) ou de points quantiques (QDs) a connu une croissance significative. Parmi ceux-ci, les QDs de sulfure de plomb (PbS) ont fait l'objet d'une attention particulière en raison de leurs propriétés exceptionnelles, notamment l'absorption optique accordable de 600 à 2600 nm. Les QDs de PbS sont considérés comme l'un des matériaux les plus prometteurs pour la prochaine génération de capteurs infrarouges. Leur utilisation dans les sphères industrielles suscite donc un intérêt croissant. Lorsque ces matériaux sont intégrés dans des dispositifs optoélectroniques, ils nécessitent l'utilisation d'électrodes efficientes d'extraction de charges, ainsi qu'un contact électrique transparent dans l'IR pour l'obtention de meilleures performances. Dans ce travail de thèse, on a étudié les propriétés des électrodes d'extraction de trous (HTL) à base d'oxydes des métaux de transition et du contact électrique transparent à base d'In2O3 (TCO ou oxyde transparent et conducteur) préparés par pulvérisation cathodique. Ces études ont été réalisées dans un premier temps sur des couches individuelles de TCO et HTL. Les caractérisations des films TCO ont permis de montrer l'intérêt du dopage à l'hydrogène sur l'amélioration de leurs propriétés optiques dans le domaine infrarouge du spectre électromagnétique (domaine d'intérêt pour les applications visées). Dans un second temps, afin de fabriquer des structures photodiodes, elles ont été intégrées sur un film de QDs de PbS déposé sur une électrode optimisée pour l'extraction et le transport d'électrons. Les caractérisations appropriées ont permis de montrer que les films ultraminces de NiOx peuvent être de meilleures alternatives aux couches de MoOx traditionnellement utilisées comme matériaux d'extraction et de transport de trous sur les films de QDs de PbSOver the past few decades, the development of zero-dimensional (0D) materials or quantum dots (QDs) has grown significantly. Among these materials, lead sulphide (PbS) QDs have received particular attention due to their outstanding properties, including tunable optical absorption from 600 to 2600 nm. PbS QDs are considered to be one of the most promising materials for the next generation of infrared sensors. There is therefore growing interest in their use in industrial applications. When these materials are integrated into optoelectronic devices, they require the use of efficient charge extraction electrodes, as well as a transparent electrical contact in the IR for better performance. In this thesis work, we studied the properties of hole extraction electrodes (HTL) based on transition metal oxides and the transparent electrical contact based on In2O3 (TCO or transparent and conductive oxide) prepared by sputtering. These studies were initially carried out on individual layers of TCO and HTL. Characterisation of the TCO films showed that hydrogen doping can improve their optical properties in the infrared region of the electromagnetic spectrum (the region of interest for the targeted applications). Secondly, in order to fabricate photodiode structures, they were integrated onto a film of PbS QDs deposited on an electrode optimised for electron extraction and transport. Appropriate characterisations have shown that ultra-thin NiOx films can be better alternatives to the MoOx layers traditionally used as hole extraction and transport materials on PbS QD films
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Cheikh, Aimane. "Etudes des hétérostructures à bases d'oxydes complexes pour de potentielles utilisations en cellules solaires". Thesis, Normandie, 2020. http://www.theses.fr/2020NORMC208.
Testo completoAbstract (sommario):
Grace à leurs propriétés fonctionnelles prometteuses, l’étude des oxydes ternaires à base de vanadium déposés sous forme de couche mince ont suscité beaucoup d’intérêt et ont fait l’objet d’une activité intense en recherche dans le domaine optoélectronique et photovoltaïque.Durant ce travail de thèse, on a étudié dans un premier temps la possibilité d’utiliser les métaux fortement corrélés tel que SrVO3 comme étant un oxyde transparent et conducteur (TCO). Pour cela, on a étudié l’évolution des propriétés optoélectroniques en fonction des conditions de croissance du SrVO3 déposé sous forme de couche mince. Dans un deuxième temps, notre étude s’est focalisée sur la réalisation d’une ingénierie de cellule solaire basée sur les hétérostructures tout oxyde de différentes bandes interdites. Pour cela, par un choix judicieux de la largeur de bande interdite de certaines pérovskites, nous avons synthétisé le LaVO3, dont l’absorption est optimale dans le spectre solaire, sur un substrat SrTiO3 sous différentes conditions de croissance. Du point de vue optique, l’étude des hétérostructures LaVO3/SrTiO3 déposé à basse pression d’oxygène a mis en évidence que le film LaVO3 possède une bande interdite de 1.18 eV se situant dans la plage optimale pour le photovoltaïque. Du point de vue électrique, l’interface polaire LaVO3/ SrTiO3 génère une couche d’interface conductrice qui servira de contact électrique pour les cellules solaires. Un autre intérêt du LaVO3 est sa structure cristalline commune à un grand nombre d’oxydes possédant des différentes valeurs des bandes interdites. Pour réaliser notre système, nous avons choisi en particulier la pérovskite LaFeO3 ayant une bande interdite de 2.2 eV, supérieure à celle du LaVO3 afin d’améliorer l’absorption optique à haute énergie. Une fois les propriétés optoélectroniques ont été établies, nous avons synthétisé l’empilement LFO/LVO sur un substrat SrTiO3 à basse pression d’oxygène. L’évolution des propriétés de notre système en fonction de l’épaisseur de LaFeO3 déposé est également étudié, mais jusqu’à présent aucune propriété de photoconductivité n’a été obtenueDue to their promising functional properties, ternary oxide thin films based on Vanadium have gained much research interest in photovoltaic technologies.During this work, we first studied the possibility to use the strongly correlated metal SrVO3 as a transparent conducting oxide (TCO). For this reason, we have studied the optoelectronic properties of SrVO3 under different growth conditions. Second, our study was focused on making band gap-graded design solar cells based on oxide heterostructures. LaVO3 is particularly interesting due to its optical band gap localized in the optimal range for harvesting solar light. Accordingly, the LaVO3 was synthetized on SrTiO3 substrate under different growth conditions. Optical measurements reveal that LaVO3/SrTiO3 heterostructure grown at low oxygen pressure possess a band gap of 1.18 eV in the ideal energy range for photovoltaic. Electrical properties show that the interface LaVO3/ SrTiO3 is conducting, serving as an electrical contact for solar cells. Another interest of LaVO3 is its crystalline structure offering the possibility to combine it with other structurally compatible transition metal oxides with larger band gap such as LaFeO3 (2.2 eV) in order to enhance the optical absorption at high energy. Once the optoelectronic properties have been established, the LFO/LVO heterostructure was synthetized on SrTiO3 substrate at low oxygen pressure. The physical properties of our system have been also investigated for different LaFeO3 thickness but, to date, no photoconductivity was obtained
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Regoutz, Anna. "Structural and electronic properties of metal oxides". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:6f425890-b211-4b35-b438-b8de18f7ae64.
Testo completoAbstract (sommario):
Metal oxides are of immense technological importance. Their wide variety of structural and electronic characteristics leads to a flexibility unrivalled by other groups of materials. However, there is still much debate about the fundamental properties of some of the most widely used oxides, including TiO2 and In2O3. This work presents high quality, in-depth characterisation of these two oxides in pure and doped form, including soft and hard X-ray photoelectron spectroscopy and X-ray diffraction. Bulk samples as well as thin film samples were prepared analysed. For the preparation of thin films a high quality sol-gel dip-coating method was developed, which resulted in epitaxial films. In more detail the organisation of the thesis is as follows: Chapter 1 provides an introduction to key ideas related to metal oxides and presents the metal oxides investigated in this thesis, In2O3, Ga2O3, Tl2O3, TiO2, and SnO2. Chapter 2 presents background information and Chapter 3 gives the practical details of the experimental techniques employed. Chapters 4 presents reciprocal space maps of MBE-grown In2O3 thin films and nanorods on YSZ substrates. Chapters 5 and 6 investigate the doping of In2O3 bulk samples with gallium and thallium and introduce a range of solid state characterisation techniques. Chapter 7 describes the development of a dip-coating sol-gel method for the growth of thin films of TiO2 and shows 3D reciprocal space maps of the resulting films. Chapter 8 concerns hard x-ray photoelectron spectroscopy of undoped and Sn-doped TiO2. Chapter 9 interconnects previous chapters by presenting 2D reciprocal space maps of nano structured epitaxial samples of In2O3 grown by the newly developed sol-gel based method. Chapter 10 concludes this thesis with a summary of the results.
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Zhang, Kelvin Hongliang. "Structural and electronic investigations of In₂O₃ nanostructures and thin films grown by molecular beam epitaxy". Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:de125918-b36f-47cc-b72d-2f3a27a96488.
Testo completoAbstract (sommario):
Transparent conducting oxides (TCOs) combine optical transparency in the visible region with a high electrical conductivity. In2O3 doped with Sn (widely, but somewhat misleadingly, known as indium tin oxide or ITO) is at present the most important TCO, with applications in liquid crystal displays, touch screen displays, organic photovoltaics and other optoelectronic devices. Surprisingly, many of its fundamental properties have been the subject of controversy or have until recently remained unknown, including even the nature and magnitude of the bandgap. The technological importance of the material and the renewed interest in its basic physics prompted the research described in this thesis. This thesis aims (i) to establish conditions for the growth of high-quality In2O3 nanostructures and thin films by oxygen plasma assisted molecular beam epitaxy and (ii) to conduct comprehensive investigations on both the surface physics of this material and its structural and electronic properties. It was demonstrated that highly ordered In2O3 nanoislands, nanorods and thin films can be grown epitaxially on (100), (110) and (111) oriented Y-stabilized ZrO2 substrates respectively. The mismatch with this substrate is -1.7%, with the epilayer under tensile strain. On the basis of ab initio density functional theory calculations, it was concluded that the striking influence of substrate orientation on the distinctive growth modes was linked to the fact that the surface energy for the (111) surface is much lower than for either polar (100) or non-polar (110) surfaces. The growth of In2O3(111) thin films was further explored on Y-ZrO2(111) substrates by optimizing the growth temperature and film thickness. Very thin In2O3 epilayers (35 nm) grew pseudomorphically under high tensile strain, caused by the 1.7% lattice mismatch with the substrate. The strain was gradually relaxed with increasing film thickness. High-quality films with a low carrier concentration (5.0 1017 cm-3) and high mobility (73 cm2V-1s-1) were obtained in the thickest films (420 nm) after strain relaxation. The bandgap of the thinnest In2O3 films was around 0.1 eV smaller than that of the bulk material, due to reduction of bonding-antibonding interactions associated with lattice expansion. The high-quality surfaces of the (111) films allowed us to investigate various aspects of the surface structural and electronic properties. The atomic structure of In2O3 (111) surface was determined using a combination of scanning tunnelling microscopy, analysis of intensity/voltage curves in low energy electron diffraction and first-principles ab initio calculations. The (111) termination has an essentially bulk terminated (1 × 1) surface structure, with minor relaxations normal to the surface. Good agreement was found between the experimental surface structure and that derived from ab initio density functional theory calculations. This work emphasises the benefits of a multi-technique approach to determination of surface structure. The electronic properties of In2O3(111) surfaces were probed by synchrotron-based photoemission spectroscopy using photons with energies ranging from the ultraviolet (6 eV) to the hard X-ray regime (6000 eV) to excite the spectra. It has been shown that In2O3 is a highly covalent material, with significant hybridization between O and In orbitals in both the valence and the conduction bands. A pronounced electron accumulation layer presents itself at the surfaces of undoped In2O3 films with very low carrier concentrations, which results from the fact the charge neutrality level of In2O3 lies well above the conduction band minimum. The pronounced electron accumulation associated with a downward band bending in the near surface region creates a confining potential well, which causes the electrons in the conduction band become quantized into two subband states, as observed by angle resolved photoemission spectra (ARPES) Fermi surface mapping. The accumulation of high density of electrons near to the surface region was found to shrink the surface band gap through many body interactions. Finally epitaxial growth of In2O3 thin films on α-Al2O3(0001) substrates was investigated. Both the stable body centred cubic phase and the metastable hexagonal corundum In2O3 phase can be stabilized as epitaxial thin films, despite large mismatches with the substrate. The growth mode involves matching small but different integral multiples of lattice planes of the In2O3 and the substrate in a domain matching epitaxial growth mode.
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"Resistivity and Optical Transmittance Simulation on Metal Embedded Transparent Conducting Oxide Thin Films". Master's thesis, 2012. http://hdl.handle.net/2286/R.I.14668.
Testo completoAbstract (sommario):
abstract: This work focuses on simulation of electrical resistivity and optical behaviors of thin films, where an Ag or Au thin layer is embedded in zinc oxide. Enhanced conductivity and transparency were earlier achieved with multilayer structured transparent conducting oxide (TCO) sandwich layer with metal (TCO/metal/TCO). Sputtering pattern of metal layer is simulated to obtain the morphology, covered area fraction, and the percolation strength. The resistivity as a function of the metal layer thickness fits the modeled trend of covered area fraction beyond the percolation threshold. This result not only presents the robustness of the simulation, but also demonstrates the influence of metal morphology in multilayer structure. Effective medium coefficients are defined from the coverage and percolation strength to obtain simulated optical transmittance which matches experimental observation. The coherence of resistivity and optical transmittance validates the simulation of the sputtered pattern and the incorporation of percolation theory in the model.Dissertation/Thesis
M.S. Materials Science and Engineering 2012
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"Enhanced Carrier Mobility in Hydrogenated and Amorphous Transparent Conducting Oxides". Doctoral diss., 2020. http://hdl.handle.net/2286/R.I.57380.
Testo completoAbstract (sommario):
abstract: The origins of carrier mobility (μe) were thoroughly investigated in hydrogenated indium oxide (IO:H) and zinc-tin oxide (ZTO) transparent conducting oxide (TCO) thin films. A carrier transport model was developed for IO:H which studied the effects of ionized impurity scattering, polar optical phonon scattering, and grain boundary scattering. Ionized impurity scattering dominated at temperatures below ~240 K. A reduction in scattering charge Z from +2 to +1 as atomic %H increased from ~3 atomic %H to ~5 atomic %H allowed μe to attain >100 cm^2/Vs at ~5 atomic %H.
In highly hydrogenated IO:H, ne significantly decreased as temperature increased from 5 K to 140 K. To probe this unusual behavior, samples were illuminated, then ne, surface work function (WF), and spatially resolved microscopic current mapping were measured and tracked. Large increases in ne and corresponding decreases in WF were observed---these both exhibited slow reversions toward pre-illumination values over 6-12 days. A hydrogen-related defect was proposed as source of the photoexcitation, while a lattice defect diffusion mechanism causes the extended decay. Both arise from an under-coordination of the In.
An enhancement of μe was observed with increasing amorphous fraction in IO:H. An increase in population of corner- and edge-sharing polyhedra consisting of metal cations and oxygen anions is thought to be the origin. This indicates some measure of medium-range order in the amorphous structure, and gives rise to a general principle dictating μe in TCOs---even amorphous TCOs. Testing this principle resulted in observing an enhancement of μe up to 35 cm^2/Vs in amorphous ZTO (a-ZTO), one of the highest reported a-ZTO μe values (at ne > 10^19 cm^-3) to date. These results highlight the role of local distortions and cation coordination in determining the microscopic origins of carrier generation and transport. In addition, the strong likelihood of under-coordination of one cation species leading to high carrier concentrations is proposed. This diverges from the historical indictment of oxygen vacancies controlling carrier population in crystalline oxides, which by definition cannot occur in amorphous systems, and provides a framework to discuss key structural descriptors in these disordered phase materials.Dissertation/Thesis
Doctoral Dissertation Materials Science and Engineering 2020
Libri sul tema "Metal oxydes and transparent conducting materials"
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Materials for Solar Cell Technologies I. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901090.
Testo completoAbstract (sommario):
The book reviews recent research and new trends in the area of solar cell materials. Topics include fabrication methods, solar cell design, energy efficiency and commercialization of next-generation materials. Special focus is placed on graphene and carbon nanomaterials, graphene in dye-sensitized solar cells, perovskite solar cells and organic photovoltaic cells, as well as on transparent conducting electrode (TCE) materials, hollow nanostructured photoelectrodes, monocrystalline silicon solar cells (MSSC) and BHJ organic solar cells. Also discussed is the use of graphene, sulfides, and metal nanoparticle-based absorber materials.
Capitoli di libri sul tema "Metal oxydes and transparent conducting materials"
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"New Generation Transparent Conducting Electrode Materials for Solar Cell Technologies". In Materials for Solar Cell Technologies I, 86–128. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901090-4.
Testo completoAbstract (sommario):
Transparent conducting electrodes (TCEs) play a vital role for the fabrication of solar cells and pivoted almost 50% of the total cost. Recently several materials have been identified as TCEs in solar cell applications. Still, indium tin oxide (ITO) based TCEs have dominated the market due to their outstanding optical transparency and electrical conductivity. However, inadequate availability of indium has increased the price of ITO based TCEs, which attracts the researchers to find alternative materials to make solar technology economical. In this regard, various kinds of conducting materials are available and synthesized worldwide with high electrical conductivity and optical transparency in order to find alternative to ITO based electrodes. Especially, new generation nanomaterials have opened a new window for the fabrication of cost effective TCEs. Carbon nanomaterials such as graphene, carbon nanotubes (CNTs), metal nanowires (MNWs) and metal mesh (MMs) based electrodes especially attracted the scientific community for fabrication of low cost photovoltaic devices. In addition to it, various conducting polymers such as poly (3, 4-ethylene dioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) based TCEs have also showed their candidacy as an alternative to ITO based TCEs. Thus, the present chapter gives an overview on materials available for the TCEs and their possible use in the field of solar cell technology
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Khan, Arshad, Shawkat Ali, Saleem Khan, Moaaz Ahmed, Bo Wang e Amine Bermak. "Vacuum-Free Fabrication of Transparent Electrodes for Soft Electronics". In Nanofibers - Synthesis, Properties and Applications. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96311.
Testo completoAbstract (sommario):
Optoelectronic devices are advancing from existing rigid configurations to deformable configurations. These developing devices need transparent electrodes (TEs) having high mechanical deformability while preserving the high electrical conductivity and optical transparency. In agreement with these requirements, vacuum-fabricated conventional TEs based on transparent conducting oxides (TCOs) are receiving difficulties due to its low abundance, film brittleness, and low optical transmittance. Novel solution-processed TE materials including regular metal meshes, metal nanowire (NW) grids, carbon materials, and conducting polymers have been studied and confirmed their capabilities to address the limitations of the TCO-based TEs. This chapter presents a comprehensive review of the latest advances of these vacuum-free TEs, comprising the electrode material classes, the optical, electrical, mechanical and surface feature properties of the soft TEs, and the vacuum-free practices for their fabrication.
Atti di convegni sul tema "Metal oxydes and transparent conducting materials"
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Ahmad, Mohammad, Zuhair Khan, Mian Muneeb Ur Rehman, Asghar Ali e Shaheer Aslam. "A Study of Aluminum Doped ZnO Thin Films Developed via a Hybrid Method Involving Sputter Deposition and Wet Chemical Synthesis". In International Symposium on Advanced Materials. Switzerland: Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/p-s02qs7.
Testo completoAbstract (sommario):
Transparent conducting oxides (TCO) are semiconducting materials that are electrically conductive as well as optically transparent thus making them suitable for application in photovoltaics, transparent heat transfer windows, electrochromic windows, flexible display, and transparent electronics. One of the methods to enhance the conductivity of metal oxides is doping, however, it can adversely affect the optical transparency of metal oxide. Aluminum (Al) doped zinc (Zn) oxide (AZO) is an important TCO material whose optoelectronic properties heavily rely on the Al doping level. There are various methods to develop AZO thin films. However, since Al and Zn are high vapor pressure materials, and their precise content control isn’t that easy, that’s why we dedicated this study to devise a facile method of Al doping into the ZnO structure. We report a twostep synthesis route to develop AZO thin films over glass substrates. Sub stoichiometric zinc oxide (ZnOx) thin films were sputter deposited over glass employing RF magnetron sputtering at 70W and 9 x 10-3 Torr Ar pressure. To mitigate Zn losses during annealing at 450 °C, the films were first oxidized up to 200 °C in air so as to convert ZnOx into stoichiometric ZnO. To incorporate Al into the ZnO structure, Al was spin coated on top of ZnO from its stabilized sol of 0.07 molar aluminum nitrate nonahydrate in ethanol. The samples were subsequently annealed at 450 °C for 2h in air with a controlled heating ramp of 3 °C/min. The film morphology, microstructure, electronic, and optical characteristics were explored employing scanning electron microscopy, energy dispersive x-ray spectroscopy, Hall effect measurements, and UV-Vis-NIR spectrophotometry, respectively. We found that both the Al and oxygen (O) content affect the optoelectronic behavior of AZO. Even without Al doping, O deficient samples were found to be sufficiently conductive, however, the ZnOx is less transparent relative to O rich stoichiometric ZnO. Furthermore, if ZnOx is annealed at higher temperatures, it causes Zn losses, since Zn is a relatively high vapor pressure material. It degrades the film morphology as well. Once we have ZnO we can confidently treat it at 450 °C to allow Al diffusion into the interiors of the ZnO film. We found that AZO produced via this method is sufficiently conductive as well as transparent.
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Lv, Chen, Xiaojing Wang, Agalya Govindasamy, Hideyuki Tsuboi, Michihisa Koyama, Akira Endou, Hiromitsu Takaba et al. "Theoretical Study on the Electronic and Structural Properties of p-Type Transparent Conducting Metal Oxides". In 2006 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 2006. http://dx.doi.org/10.7567/ssdm.2006.p-9-3.
Testo completo
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Farvid, Shokouh S., Ting Wang e Pavle V. Radovanovic. "Spectroscopic and magnetic properties of colloidal transition metal-doped transparent conducting oxide nanocrystals as building blocks for spintronic materials". In SPIE NanoScience + Engineering, a cura di Henri-Jean M. Drouhin, Jean-Eric Wegrowe e Manijeh Razeghi. SPIE, 2010. http://dx.doi.org/10.1117/12.860894.
Testo completo
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Lee, Yohan, Sun-Je Kim e Byoungho Lee. "Transmission-type active amplitude modulator with indium tin oxides". In JSAP-OSA Joint Symposia. Washington, D.C.: Optica Publishing Group, 2017. http://dx.doi.org/10.1364/jsap.2017.8a_pb2_8.
Testo completoAbstract (sommario):
Recent studies have focused on the demonstration of active nano-devices whose optical properties can be controlled electrically for applications. Studies using electro-optical materials, such as graphene, phase change materials, and transparent conducting oxides have been reported [1-3]. In particular, indium tin oxides (ITOs) have attracted a lot of attention owing to outstanding electro-optical characteristics, where the refractive index change reaches unity if biased in near-infrared range. However, the thickness of charge accumulation layer of which the refractive index changes is about only 1 nm when electric field is applied on ITO. In addition, owing to the structural limitation for applying the voltage, so far, only research on reflection-type with metal layers has been reported.