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Book Optimisation of ZnO Thin Films

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.

Book The Optimization of Thin Film P CuO n ZnO Heterostructures for Use in Selective Gas Detection

Download or read book The Optimization of Thin Film P CuO n ZnO Heterostructures for Use in Selective Gas Detection written by Christopher S. Dandeneau and published by . This book was released on 2009 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since bulk p-CuO/n-ZnO heterocontacts were first proposed for gas detection, rapid development has taken place in improving the overall functionality of these structures. While bulk heterocontacts have been shown to exhibit desirable sensitivity and selectivity characteristics, these devices suffer from innate diffusion and ZnO/CuO connectivity drawbacks that limit their effective use. To address these issues, thin film p-CuO/n-ZnO heterostructures have been fabricated via wet chemical (sol-gel) processes so as to examine their potential use in reducing environments. Individual ZnO and CuO sol-gel processes have been developed with the goal of optimizing thin film porosity, crystallinity, and preferred orientation for enhanced gas sensing capability. Particular attention was given to the effects of solution chemistry and pyrolysis temperature on desired thin film properties. For ZnO, control over film microstructure was attained through fabrication modes based on the solvents 2-methoxyethanol (MOE) and dimethylformamide (DMF). Monoethanolamine (MEA) was employed as a chelating ligand in specific solutions. Optimum preferred orientation for DMF-based ZnO films was seen to exist at a solution chemistry of 5% water and a 1:1 molar ratio of Zn to MEA. An increase in the drying temperature yielded a monotonic decrease in the electrical resistivity of these films. For the MOE-based process, a lowering of the pyrolysis temperature led to an increase in ZnO film porosity. CuO thin films were deposited through a solution route based on isopropanol. Scanning electron microscopy (SEM) revealed the CuO films to possess a level of porosity much higher than that seen in the ZnO films. Thin film p-CuO/n-ZnO heterostructures were fabricated in two configurations; ZnO on CuO (ZnO/CuO) and CuO on ZnO (CuO/ZnO). The results of current-voltage (I-V) tests showed the CuO/ZnO structures to display enhanced sensing characteristics to 4000 ppm hydrogen when compared to the ZnO/CuO structures. This finding was attributed to the inherently high porosity of the top CuO layer which in turn allowed for improved gas diffusion to the heterostructure interface. The phase equilibrium between CuO and ZnO exhibits limited solubility. As such, a novel microstructure formed by combining CuO and ZnO precursors has been explored with the expectation that the films will phase separate. For the deposited films, a variance in both the annealing temperature and time was found to yield a microstructure comprised of individual ZnO and CuO grains. The co-existence of these two structures was confirmed through Energy Dispersive Spectroscopy (EDS). It is expected that the high level of connectivity between the ZnO and CuO along with negligible barriers to gas diffusion will lead to superior sensing characteristics.

Book Fabrication of ZnO Thin Film Through Chemical Preparations

Download or read book Fabrication of ZnO Thin Film Through Chemical Preparations written by Ersan Y. Muslih and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) is a compound that has unique physical and chemical properties. It has a direct band gap at 3.4 eV (without dopant), a high bonding energy (60 meV), and a high thermal and mechanical stability at room temperature. Thus, ZnO thin film can be suitably applied in many fields, and it also has many functions such as UV light emitters, hydrophobic coating, transparent thin film in electronic devices, piezoelectric material, transducers, gas-sensing, and a transparent conductive oxide (TCO) layer in thin film solar cells. ZnO thin film could be prepared by many chemical preparations such as chemical bat deposition (CBD), chemical vapor deposition (CVD), sol-gel spin coating, doctor blade, printing deposition, and electrochemical deposition (ED). This chemical process is a low-cost, simple, and easy preparation process to be adjusted or doped by other elements.

Book Zno Thin Film Electronics For More Than Displays

Download or read book Zno Thin Film Electronics For More Than Displays written by Jose Ramirez and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide thin film transistors (TFTs) are investigated in this work for large-area electronic applications outside of display technology. A constant pressure, constant flow, showerhead, plasma-enhanced atomic layer deposition (PEALD) process has been developed to fabricate high mobility TFTs and circuits on rigid and flexible substrates at 200 °C. ZnO films and resulting devices prepared by PEALD and pulsed laser deposition (PLD) have been compared. Both PEALD and PLD ZnO films result in densely packed, polycrystalline ZnO thin films that were used to make high performance devices. PEALD ZnO TFTs deposited at 300 °C have a field-effect mobility of ~ 40 cm2/V-s (and > 20 cm2/V-S deposited at 200 °C). PLD ZnO TFTs, annealed at 400 °C, have a field-effect mobility of > 60 cm2/V-s (and up to 100 cm2/V-s). Devices, prepared by either technique, show high gamma-ray radiation tolerance of up to 100 Mrad(SiO2) with only a small radiation-induced threshold voltage shift (VT ~ -1.5 V). Electrical biasing during irradiation showed no enhanced radiation-induced effects. The study of the radiation effects as a function of material stack thicknesses revealed the majority of the radiation-induced charge collection happens at the semiconductor-passivation interface. A simple sheet-charge model at that interface can describe the radiation-induced charge in ZnO TFTs. By taking advantage of the substrate-agnostic process provided by PEALD, due to its low-temperature and excellent conformal coatings, ZnO electronics were monolithically integrated with thin-film complex oxides. Application-based examples where ZnO electronics provide added functionality to complex oxide-based devices are presented. In particular, the integration of arrayed lead zirconate titanate (Pb(Zr, Ti)O3 or PZT) thin films with ZnO electronics for microelectromechanical systems (MEMs) and deformable mirrors is demonstrated. ZnO switches can provide voltage to PZT capacitors with fast charging and slow discharging time constants. Finally, to circumvent fabrication challenges on predetermined complex shapes, like curved mirror optics, a technique to transfer electronics from a rigid substrate to a flexible substrate is used. This technique allows various thin films, regardless of their deposition temperature, to be transferred to flexible substrates. Finally, ultra-low power operation of ZnO TFT gas sensors was demonstrated. The ZnO ozone sensors were optimized to operate with excellent electrical stability in ambient conditions, without using elevated temperatures, while still providing good gas sensitivity. This was achieved by using a post-deposition anneal and by partially passivating the contact regions while leaving the semiconductor sensing area open to the ambient. A novel technique to reset the gas sensor using periodic pulsing of a UV light over the sensor results in less than 25 milliseconds recovery time. A pathway to achieve gas selectivity by using organic thin-film layers as filters deposited over the gas sensors tis demonstrated. The ZnO ozone sensor TFTs and the UV light operate at room temperature with an average power below 1 [mu]W.

Book Fabrication of Lead Free and Lead Based 1 3 Piezoelectric Composites for High Frequency Ultrasound Transducers

Download or read book Fabrication of Lead Free and Lead Based 1 3 Piezoelectric Composites for High Frequency Ultrasound Transducers written by Tanikan Thongchai and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is concerned with the fabrication and characterisation of lead free piezocomposites and transducers for use in high frequency medical ultrasound imaging applications. A water based gel casting and micro moulding approach has been developed to fabricate 1-3 composites with a random pillar structure in the lead free and lead based piezoelectric material. High frequency transducers incorporating the random composites as the active components have been fabricated, characterised and demonstrated in real tissue imaging environments. A water based gel casting system has been used incorporating Hydantoin Epoxy resin, amine hardener (Bis (3-aminoproply) amine) and dispersant. Viscosities of the 50BCZT and PZT systems were minimised by the addition of 2.4 and 1 wt% of dispersant respectively. The highest values of piezoelectric and dielectric properties corresponded to 50BCZT samples fabricated with a gel casting slurry incorporating 30 wt% resin and sintered at 1425 °C, with d33 and kp values of 330 pC/N and 0.43, respectively. 1-3 composites were successfully fabricated from the BCZT and PZT bristle block structures and only one resonance peak corresponding to the thickness mode was observed. PZT composites offered generally higher thickness coupling coefficients than 50BCZT composites, where the highest value of 0.78 was measured for samples sintered at temperature 1425 °C. Focused PZT, focused 50BCZT, unfocussed PZT and unfocussed 50BCZT transducers were successfully fabricated using the composites with randomised structure, and have operating frequencies of 35, 40, 50 and 35 MHz respectively.

Book 2015 ICU International Congress on Ultrasonics Abstract Book Metz France Declercq N F editor 2015

Download or read book 2015 ICU International Congress on Ultrasonics Abstract Book Metz France Declercq N F editor 2015 written by Nico F. Declercq and published by Nico F. Declercq. This book was released on 2015-05-11 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The compilation of this book has been made possible with the help of Didier Cassereau, Bertrand Dubus and John Fritsch with support from the Scientific and Technical Committee of 2015 ICU.

Book Electrical Electronics Abstracts

Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 2092 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Power Ultrasound in Electrochemistry

Download or read book Power Ultrasound in Electrochemistry written by Bruno Pollet and published by John Wiley & Sons. This book was released on 2012-01-03 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of power ultrasound to promote industrial electrochemical processes, or sonoelectrochemistry, was first discovered over 70 years ago, but recently there has been a revived interest in this field. Sonoelectrochemistry is a technology that is safe, cost-effective, environmentally friendly and energy efficient compared to other conventional methods. The book contains chapters on the following topics, contributed from leading researchers in academia and industry: Use of electrochemistry as a tool to investigate Cavitation Bubble Dynamics Sonoelectroanalysis Sonoelectrochemistry in environmental applications Organic Sonoelectrosynthesis Sonoelectrodeposition Influence of ultrasound on corrosion kinetics and its application to corrosion tests Sonoelectropolymerisation Sonoelectrochemical production of nanomaterials Sonochemistry and Sonoelectrochemistry in hydrogen and fuel cell technologies

Book Micromachined Ultrasonic Transducers

Download or read book Micromachined Ultrasonic Transducers written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microfabricated ultrasonic transducers have been generated which operate in both liquids and gases. Air coupled through transmission of aluminum was observed for the first time using a pair of 2.3 MHz transducers. The dynamic range of the transducers was 110 dB, and the received signal had an SNR of 30 dB. Air coupled through transmission of steel and glass has also been observed. A theoretical model for the transducers has been refined and agrees well with experimental results. A robust microfabrication process has been developed and was used to generate air transducers which resonate from 2 to 12 MHz, as well as immersion transducers that operate in water from 1 to 20 MHz with a 60 dB dynamic range. Optimized immersion and air transducers have been designed and a dynamic range above 110 dB is anticipated. This development effort finds applications in hydrophones, medical ultrasound, nondestructive evaluation, ranging, flow metering, and scanning tip force sensing and lithography.

Book Dissertation Abstracts International

Download or read book Dissertation Abstracts International written by and published by . This book was released on 1998 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Piezoelectric Energy Harvesting

Download or read book Piezoelectric Energy Harvesting written by Alper Erturk and published by John Wiley & Sons. This book was released on 2011-04-04 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transformation of vibrations into electric energy through the use of piezoelectric devices is an exciting and rapidly developing area of research with a widening range of applications constantly materialising. With Piezoelectric Energy Harvesting, world-leading researchers provide a timely and comprehensive coverage of the electromechanical modelling and applications of piezoelectric energy harvesters. They present principal modelling approaches, synthesizing fundamental material related to mechanical, aerospace, civil, electrical and materials engineering disciplines for vibration-based energy harvesting using piezoelectric transduction. Piezoelectric Energy Harvesting provides the first comprehensive treatment of distributed-parameter electromechanical modelling for piezoelectric energy harvesting with extensive case studies including experimental validations, and is the first book to address modelling of various forms of excitation in piezoelectric energy harvesting, ranging from airflow excitation to moving loads, thus ensuring its relevance to engineers in fields as disparate as aerospace engineering and civil engineering. Coverage includes: Analytical and approximate analytical distributed-parameter electromechanical models with illustrative theoretical case studies as well as extensive experimental validations Several problems of piezoelectric energy harvesting ranging from simple harmonic excitation to random vibrations Details of introducing and modelling piezoelectric coupling for various problems Modelling and exploiting nonlinear dynamics for performance enhancement, supported with experimental verifications Applications ranging from moving load excitation of slender bridges to airflow excitation of aeroelastic sections A review of standard nonlinear energy harvesting circuits with modelling aspects.

Book Thin Film Shape Memory Alloys

Download or read book Thin Film Shape Memory Alloys written by Shuichi Miyazaki and published by Cambridge University Press. This book was released on 2009-09-03 with total page 487 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first dedicated book describing the properties, preparation, characterization and device applications of TiNi-based shape memory alloys.

Book Chemical Abstracts

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt: