Download or read book Novel Diluted Magnetic Semiconductor Materials based on Zinc Oxide written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary aim of this work was to develop a ZnO based diluted magnetic semiconductor (DMS) materials system which displays ferromagnetism above room temperature and to understand the origin of long-range ferromagnetic ordering in these systems. Recent developments in the field of spintronics (spin based electronics) have led to an extensive search for materials in which semiconducting properties can be integrated with magnetic properties to realize the objective of successful fabrication of spin-based devices. For these devices we require a high efficiency of spin current injection at room temperature. Diluted magnetic semiconductors (DMS) can serve this role, but they should not only display room temperature ferromagnetism (RTFM) but also be capable of generating spin polarized carriers. Transition metal doped ZnO has proved to be a potential candidate as a DMS showing RTFM. The origin of ferromagnetic ordering in ZnO is still under debate. However, the presence of magnetic secondary phases, composition fluctuations and nanoclusters could also explain the observation of ferromagnetism in the DMS samples. This encouraged us to investigate Cu-doped(+ ư spin in the 2+ valence state) ZnO system as a probable candidate exhibiting RTFM because neither metallic Cu nor its oxides (Cu2O or CuO) are ferromagnetic. The role of defects and free carriers on the ferromagnetic ordering of Cu-doped ZnO thin films was studied to ascertain the origin of ferromagnetism in this system. A novel non-equilibrium Pulsed Laser Deposition technique has been used to grow high quality epitaxial thin films of Cu:ZnO and (Co, Cu):ZnO on c-plane Sapphire by domain matching epitxay. Both the systems showed ferromagnetic ordering above 300K but Cu ions showed a much stronger ferromagnetic ordering than Co, especially at low concentrations (1-2 %) of Cu where we realized near 100% polarization. But, the incorporation of Cu resulted in a 2-order of magnitude rise in the resistivity from 10-1 t.
Download or read book Novel Diluted Magnetic Semiconductor Materials Based on Zinc Oxide written by Deepayan Chakraborti and published by . This book was released on 2007 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: Cu doped ZnO, Thin Film Epitaxy, Structure-Property Correlation, Ferromagnetism, Spintronic, Magnetoresistance.
Download or read book Zinc Oxide based Diluted Magnetic Semiconductors written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During my graduate research I have synthesized materials known as diluted magnetic semiconductors (DMS) as epitaxial thin film structures using the process of pulsed laser deposition (PLD). These materials are envisioned to be of importance in the emerging field of spintronics where the charge as well as the spin of the charge carriers can be combined to yield unique functionalities to yield novel devices including, on-chip memories, ultra-low power devices etc. The material of interest in this dissertation was zinc oxide, a wide bandgap optoelectronic semiconductor. ZnO has a bandgap of 3.3 eV. It is an ideal candidate for spintronics applications, because Zn is the last of the first row transition metals, which leads to pretty high solubility of transition metals such as Co, Mn and V in ZnO. In a diluted magnetic semiconductor a fraction of the host atoms is substituted by the transition metal dopant ion. We have found that we can synthesize very high quality, single phase and single crystalline Zn(TM)O thin films on basal plane sapphire single crystals (a-Al2O3). We have analyzed the magnetic properties of the three systems of ZnVO, ZnCoO and ZnMnO and found that ZnCoO and ZnMnO exhibit ferromagnetic ordering up to room temperature, when synthesized under high vacuum. In these conditions, the samples have a reasonable concentration of point defects which drive ZnO to n-type conductivity. By a combination of insitu and exsitu variation of parameters we have been able to tune the electronic and magnetic properties of these systems. From these studies we conclude that the main mechanism of magnetic ordering in these DMS materials is through a combination of defect related carrier induced exchange and bound magnetic polaron exchange. Device structures were fabricated using the as deposited samples to study the possibility of spin injection through semiconductors. We have observed that at low temperatures we see a considerable effect from this phenomenon in a m.
Download or read book Thin Films of Mn doped Zinc Oxide Diluted Magnetic Semiconductor Materials Spintronics written by Usman Ilyas and published by . This book was released on 2014 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Zinc Oxide Based Diluted Magnetic Semiconductors written by Shivaraman Ramahandran and published by . This book was released on 2006 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: optoelectronics, spintronics, magneto-transport, thin films, magnetic, Diluted magnetic semiconductors, epitaxy, transmission electron microscopy, tunnel junction, magneto-resistance, spin injection.
Download or read book Structural Electronic and Magnetic Properties of Diluted Magnetic Semiconductors Based on Transition Metals Doped Zinc Oxide written by Bakhtiar Ul Haq and published by . This book was released on 2014 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Zinc Oxide and Related Materials written by Zhe Chuan Feng and published by Taylor & Francis. This book was released on 2012-09-26 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through their application in energy-efficient and environmentally friendly devices, zinc oxide (ZnO) and related classes of wide gap semiconductors, including GaN and SiC, are revolutionizing numerous areas, from lighting, energy conversion, photovoltaics, and communications to biotechnology, imaging, and medicine. With an emphasis on engineering a
Download or read book Origin of Magnetism in Oxide Based Diluted Magnetic Semiconductors written by Numan Akdogan and published by LAP Lambert Academic Publishing. This book was released on 2014-07-23 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spintronics, short notation for spin-based electronics, is a research area which seeks to exploit the spin of electrons in addition to their charge in semiconductors. The basic idea is to combine the characteristics of existing magnetic devices with semiconductor devices in order to realize a new generation of devices that are much smaller, more energy efficient, non-volatile, and much faster than presently available. The key requirement in the development of such devices is an efficient injection, transfer and detection of spin-polarized current from a ferromagnetic material into a semiconductor. Due to the well known problem of a resistance mismatch at metal/semiconductor interfaces, hindering an effective spin injection, much interest is concentrated on the development of room-temperature ferromagnetic semiconductors. The aim of this book is to shed some light on the origin of room temperature ferromagnetism in oxide-based DMS materials whether it originates from clusters or from uniformly distributed magnetic atoms.
Download or read book Novel Functional Magnetic Materials written by Arcady Zhukov and published by Springer. This book was released on 2016-03-03 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents current research on advanced magnetic materials and multifunctional composites. Recent advances in technology and engineering have resulted from the development of advanced magnetic materials with improved functional magnetic and magneto-transport properties. Certain industrial sectors, such as magnetic sensors, microelectronics, and security, demand cost-effective materials with reduced dimensionality and desirable magnetic properties such as enhanced magnetic softness, giant magnetic field sensitivity, and large magnetocaloric effect. Expert chapters present the most up-to-date information on the fabrication process, processing, tailoring of properties, and applications of different families of modern functional materials for advanced smart applications. Topics covered include novel magnetic materials and applications; amorphous and nanocrystalline magnetic materials and applications; hard magnetic materials; magnetic shape memory alloys; and magnetic oxides. The book's highly interdisciplinary and forward-looking approach will benefit the scientific community, particularly researchers and advanced graduate students working in the field of advanced magnetic materials, composites, and high-performance sensor and microwave devices.
Download or read book Transition Metal Doped Zinc Oxide as Diluted Magnetic Semiconductor written by Zheng Zuo and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Thin Film Electronics with Novel Materials written by Yiyang Gong and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Novel materials, including zinc oxide (ZnO) and 2D transition metal dichalcogenides (TMDs), have been investigated in this dissertation for the realization of high-performance large-area integrated circuits. These novel materials may provide differential advantages over the established large-area thin film technology based on silicon, which has been extensively employed in applications such as large-area flat panel displays, high-speed active matrix thin film circuits, flexible and wearable electronics, etc. The dissertation begins with the discussion of high-performance plasma-enhanced atomic layer deposition (PEALD) of ZnO thin films and ZnO thin film transistors (TFTs) with a field effect mobility of ~ 10 to 20 cm2/Vs, which have been demonstrated. Offset-drain ZnO TFTs, which are able to withstand or switch voltage beyond 80 V, have also been demonstrated. These results shed light on the realization of large-area active-matrix circuits beyond the capabilities of the current display industry where high circuit speed or high operation voltage is required. To further improve the performance of ZnO-based electronics, many related materials, including doped ZnO, zinc nitride, and aluminum nitride, have been investigated. Doped ZnO has been proposed as the carrier injection layer that can improve the conductivity of metal-semiconductor contact in ZnO TFTs. Aluminum-doped ZnO thin films have been deposited using triisobutyl aluminum (TIBA) as the dopant precursor instead of trimethyl aluminum (TMA) in order to improve the uniformity of dopant distribution because TIBA has much lower vapor pressure than TMA. AZO thin films with resistivity ~ 10-2 cm have been achieved by PEALD. Besides, aluminum nitride and zinc nitride thin films have also been studied using PEALD. In addition to the showerhead PEALD system, a novel inductively coupled plasma ALD system has been designed and set up that provides RF power up to 500 W in order to generate a highly reactive nitrogen plasma source and enable the deposition of high-quality metal nitride at relatively low temperature. These metal nitride thin films may provide additional building blocks to enhance the speed and thermal stability of ZnO-based thin film devices and circuits.Owing to their excellent electrical and mechanical properties, 2D-TMD thin films have been studied for flexible electronics applications. High quality MoS2 and WS2 thin films have been achieved via mechanical exfoliation and chemical vapor deposition. To fabricate MoS2- and WS2-based TFTs, a 5-step device fabrication process has been developed, which is compatible to both the conventional rigid substrate and the ~ 4.8 nm thick solution-cast polyimide (PI) flexible substrate. The MoS2 and WS2 TFTs fabricated on PI substrate exhibit a field effect mobility of between 1 to 20 cm2/Vs, which is similar to that of those fabricated on rigid silicon substrate. More importantly, extraordinary mechanical strength and stability have been demonstrated for MoS2 and WS2 TFTs fabricated on PI substrate. A reasonably small degradation in device performance has been observed in these flexible 2D-TMD TFTs under static bending to the radius of ~ 2mm and after cyclic bending up to 100,000 cycles. Finally, attempts to create integratable 2D-TMD circuits have been demonstrated. To realize large-area 2D-TMD based circuits, growth of wafer-scale continuous WSe2 thin films has been demonstrated using metal organic chemical vapor deposition (MOCVD). Deposition has been achieved at as low as 400 C, which allows deposition on glass and polymeric substrate and enables the transfer-free fabrication of WSe2 TFTs and circuits on arbitrary platforms. Patterning and post-growth thickness modulation of continuous WSe2 thin film have been demonstrated using CF4 plasma and O2 plasma, whereby high-speed etching and nanometer-scale film thinning can be realized. With the capability of depositing and patterning wafer-scale WSe2 thin films, an array of p-channel WSe2 TFTs have been fabricated with a field effect mobility of ~0.01 cm2/Vs and an on-off ratio greater than 104.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 906 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ZnO based Diluted Magnetic Semiconductors for Applications in the Field of Spintronics written by Mariana-Mihaela Ungureanu and published by . This book was released on 2007 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Nonmagnetic Doping and Growth Temperature on the Magneto transport Properties of Mangenese sic and Cobalt Doped Zinc Oxide Dilute Magnetic Semiconductors written by Govind Mundada and published by . This book was released on 2006 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Zinc Oxide and Related Materials Volume 957 written by Jürgen H. Christen and published by . This book was released on 2007-04-05 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners. The topics covered in this volume, first published in 2007, include devices, defects, spintronics and magnetism, growth, optical properties and nanostructures, and doping and processing TFTs.
Download or read book Zinc Oxide Materials and Devices written by Ferechteh Hosseini Teherani and published by Society of Photo Optical. This book was released on 2006 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes Proceedings Vol. 7821
