Author: Nicolaos Alkiviadis Economou
Publisher:
ISBN:
Category :
Languages : en
Pages : 110

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Author: Layman Austin Lott
Publisher:
ISBN:
Category : Copper oxide
Languages : en
Pages : 116

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Book Description

Author: Longcheng Wang
Publisher: ProQuest
ISBN: 9780549387589
Category : Copper oxide
Languages : en
Pages :

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Book Description
Copper oxides, including cuprous oxide and cupric oxide, are prepared by electrochemical deposition. The structural, optical and electrical properties of as-deposited copper oxides are evaluated, based on which cuprous oxide is selected as a promising material for photovoltaic applications. Electrodeposited cuprous oxide is a p-type semiconductor with a direct band gap of 2.06 eV. The mechanism of how pH affects the structural and electrical properties of electrodeposited cuprous oxide films is studied. In the pH range of 7.5 to 12.0, there are three different preferred crystal orientations: (100), (110) and (111). With different orientations, cuprous oxide shows different surface morphology and grain size. Bath pH effect on structural properties is explained by its effect on the growth rate of different crystallographic planes with different Cu+/O2- ratios. Capacitance-voltage measurements are performed to study electrical properties of differently oriented cuprous oxide films. The results show that the flat band potential shifts negatively as the bath pH increases. Electrodeposited cupric oxide is a p-type cupric oxide with an indirect band gap of 1.32 eV. Different cleaning methods are used to clean the substrate surface for electrodeposition of cupric oxide. Electrochemical etching is proven to be an effective method for Cu substrate cleaning in cupric oxide deposition. In particular, in-situ electrochemical etching is developed, which prevents the cleaned substrate from exposure to air. Current-voltage characterization shows that cupric oxide deposited on electrochemically etched Cu substrates has favorable electrical properties and better rectification behavior. Cuprous oxide is selected for the fabrication of p-n homo-junction because it has better crystallinity, bigger grains, better control over crystal quality and a direct band gap. Based on the model that bath pH can control the stoichiometry and native point defects in electrodeposited cuprous oxide films, both p-type and n-type cuprous oxides are successfully deposited at different bath pH values. For samples deposited at pH below 7.5, cuprous oxides are n-type semiconductors, while at bath pH above 9.0, cuprous oxides are p-type semiconductors. Furthermore, a two-step deposition process is developed to fabricate a p-n homo-junction in cuprous oxide. Current-voltage measurements show a typical rectification behavior of a p-n junction for these samples, which suggest that a p-n homo-junction of cuprous oxide is achieved, which is, to our knowledge, the first p-n homo-junction of cuprous oxide prepared by any method. The significance of this invention is because it enables the fabrication of solar cell with a reasonable high conversion efficiency (& sim;10%) at a very low cost.

Author: Yiyi Yang
Publisher:
ISBN:
Category : Cuprous oxide
Languages : en
Pages : 159

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Book Description
Cuprous oxide (Cu2O) is a promising material for the fabrication of oxide solar cells due to its abundance, nontoxicity, stability and ability to be deposited under mild conditions. At the moment, the reported efficiencies for Cu2O-based solar cells are well below its theoretical limit and most of the high performance devices are fabricated using energy-intensive processes. Electrodeposition of Cu2O thin films is a well-known process although a systematic study of the dependence of Cu2O film properties on the deposition conditions has not been reported, especially in the context of photovoltaic applications. The purpose of this study is to optimize the electrodeposited p-type Cu2O film properties for the application in heterojunction solar cells through the manipulation of electrodeposition conditions. A range of Cu2O morphologies are formed by varying the parameters during the constant potential deposition of Cu2O thin films from a copper-lactate electrolyte including applied potential, temperature, pH, copper concentration and lactate concentration. The variation in morphology is mostly attributed to the relative growth rates of 111 and 100 orientations. It is found that the variation in growth orientation is mostly due to the relative rates or reaction and transport. When reaction kinetics is the limiting factor, 100 growth is preferred when the conditions are close to thermodynamic equilibrium. On the other hand, when transport limitation in the system is significant, 111-oriented growth and cubic grains are favored as the surface concentration of CuLac2 is reduced. In other conditions, mixed orientations tend to be formed. Evidence of adsorption of lactate ions onto the (111) faces is also observed, promoting 100 directed growth at high lactate concentration. In addition, significant evidence of film dissolution during deposition is observed at high electrolyte pH of 13 and above. The performance of Cu2O thin films in photovoltaic devices is evaluated using an FTO/Cu2O/AZO cell structure. It is found that the electrolyte pH has the most prominent effect on the device performance among different electrodeposition parameters. Performance variables including JSC, VOC and FF all improve significantly as the Cu2O deposition pH increases. An optimal cell efficiency of ~1.55% is obtained using Cu2O thin films deposited at a high pH of 13.4, which exceeds the majority of previously reported efficiencies using the same deposition technique. The reason for the improved efficiency is attributed to the dissolution and reformation of Cu2O grains during deposition at high pH through the improvement of charge carrier mobility and band gap in the Cu2O layer. Film orientation of Cu2O also plays a minor role in cell efficiency. Alternative electrodeposition procedures are investigated. Galvanostatic deposition is found to be less suitable than potentiostatic deposition for solar cell fabrication due to the difficulty in controlling Cu metal content in the film. Evidence of dissolution by oxidation is observed under both pulsed and stirred conditions. Different morphologies to the typical polyhedral shapes with higher carrier concentration and low carrier mobility are obtained in both cases. These effects are attributed to the lowering of diffusion limitations during the deposition process either by allowing more time for transport or by increasing transport rate. These processes result in lower device performance compared to potentiostatic deposition under similar conditions. Finally, FTO/Cu2O/ZnO devices are fabricated by depositing ZnO onto electrodeposited Cu2O layer through a seed-layer assisted chemical growth method in zinc nitrate-HMTA solution. Ordered ZnO nanorods are obtained using this technique and their dimensions can be controlled by adjusting bath compositions. Smooth ZnO thin films with no pin-hole defects are obtained although the performance of Cu2O/ZnO devices is not as high as devices with AZO layers.

Author: Fabian I. Ezema
Publisher: Springer Nature
ISBN: 3030684628
Category : Technology & Engineering
Languages : en
Pages : 926

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Book Description
This book guides beginners in the areas of thin film preparation, characterization, and device making, while providing insight into these areas for experts. As chemically deposited metal oxides are currently gaining attention in development of devices such as solar cells, supercapacitors, batteries, sensors, etc., the book illustrates how the chemical deposition route is emerging as a relatively inexpensive, simple, and convenient solution for large area deposition. The advancement in the nanostructured materials for the development of devices is fully discussed.

Author: United States. Air Force. Office of Scientific Research
Publisher:
ISBN:
Category : Research
Languages : en
Pages : 940

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Book Description

Author: Mordechay Schlesinger
Publisher: John Wiley & Sons
ISBN: 0470167785
Category : Science
Languages : en
Pages : 755

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Book Description
The definitive resource for electroplating, now completely up to date With advances in information-age technologies, the field of electroplating has seen dramatic growth in the decade since the previous edition of Modern Electroplating was published. This expanded new edition addresses these developments, providing a comprehensive, one-stop reference to the latest methods and applications of electroplating of metals, alloys, semiconductors, and conductive polymers. With special emphasis on electroplating and electrochemical plating in nanotechnologies, data storage, and medical applications, the Fifth Edition boasts vast amounts of new and revised material, unmatched in breadth and depth by any other book on the subject. It includes: Easily accessible, self-contained contributions by over thirty experts Five completely new chapters and hundreds of additional pages A cutting-edge look at applications in nanoelectronics Coverage of the formation of nanoclusters and quantum dots using scanning tunneling microscopy (STM) An important discussion of the physical properties of metal thin films Chapters devoted to methods, tools, control, and environmental issues And much more A must-have for anyone in electroplating, including technicians, platers, plating researchers, and metal finishers, Modern Electroplating, Fifth Edition is also an excellent reference for electrical engineers and researchers in the automotive, data storage, and medical industries.

Author: Vitaly Gurylev
Publisher: Springer Nature
ISBN: 3030819116
Category : Technology & Engineering
Languages : en
Pages : 388

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Book Description
This book helps readers comprehend the principles and fundamentals of defect engineering toward realization of an efficient photocatalyst. The volume consists of two parts, each of which addresses a particulate type of defects. The first, larger section provides a comprehensive and rigorous treatment of the behaviour and nature of intrinsic defects. The author describes how their controlled introduction and consequent manipulation over concentration, distribution, nature and diffusion is one of the most effective and practical methodologies to modify the properties and characteristics of target photocatalytic materials. The second part of the book explains the formation of extrinsic defects in the form of metallic and non-metallic dopants and gives a detailed description of their characteristics as this approach is also often used to fabricate an efficient photocatalyst. Filling the gap in knowledge on the correlation between introduction of defects in various semiconducting materials and their photocatalytic performance, the book is ideal for graduate students, academics and researchers interested in photocatalysts, defect engineering, clean energy, hydrogen production, nanoscale advanced functional materials, CO2 deactivation, and semiconductor engineering.

Author: Mahmoud Abdelfatah
Publisher: Cuvillier Verlag
ISBN: 3736982968
Category : Technology & Engineering
Languages : en
Pages : 130

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Book Description
The low cost and low temperature electrochemical deposition technique was employed to grow Cu2O thin films and ZnO:Al thin films were deposited by d.c. magnetron sputtering in order to fabricate solar cells. The potentiostatic and galvanostatic electrodeposition modes were used to deposit the Cu2O thin films. Raman spectra of thin films have shown characteristic frequencies of crystalline Cu2O. The contact between Cu2O and Au is found to be an Ohmic contact. The devices grown by a potentiostatic mode have higher efficiency than those grown by a galvanostatic mode. The optimum thickness of Cu2O thin films as an absorber layer in solar cells. was found to be around 3 µm respect to a high efficiency. Flexible and light weight solar cell was fabricated on plastic substrate.

Author: Stuart Bogatko
Publisher:
ISBN:
Category : Thin films
Languages : en
Pages : 130

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Book Description