Synthesis and Characterization of Silver Doped Zinc Oxide Thin Films for Optoelectronic Devices PDF Download

Author: Fernando Lugo
Publisher:
ISBN: 9781124131412
Category :
Languages : en
Pages : 0

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Author: Michelle Anne Myers
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Applications of zinc oxide (ZnO) for optoelectronic devices, including light emitting diodes, semiconductor lasers, and solar cells have not yet been realized due to the lack of high-quality p-type ZnO. In the research presented herein, pulsed laser deposition is employed to grow Ag-doped ZnO thin films, which are characterized in an attempt to understand the ability of Ag to act as a p-type dopant. By correlating the effects of the substrate temperature, oxygen pressure, and laser energy on the electrical and microstructural properties of Ag-doped ZnO films grown on c-cut sapphire substrates, p-type conductivity is achieved under elevated substrate temperatures. Characteristic stacking fault features have been continuously observed by transmission electron microscopy in all of the p-type films. Photoluminescence studies on n-type and p-type Ag-doped ZnO thin films demonstrate the role of stacking faults in determining the conductivity of the films. Exciton emission attributed to basal plane stacking faults suggests that the acceptor impurities are localized nearby the stacking faults in the n-type films. The photoluminescence investigation provides a correlation between microstructural characteristics and electrical properties of Ag- doped ZnO thin films; a link that enables further understanding of the doping nature of Ag impurities in ZnO. Under optimized deposition conditions, various substrates are investigated as potential candidates for ZnO thin film growth, including r -cut sapphire, quartz, and amorphous glass. Electrical results indicated that despite narrow conditions for obtaining p-type conductivity at a given substrate temperature, flexibility in substrate choice enables improved electrical properties. In parallel, N+-ion implantation at elevated temperatures is explored as an alternative approach to achieve p-type ZnO. The ion implantation fluence and temperature have been optimized to achieve p-type conductivity. Transmission electron microscopy reveals that characteristic stacking fault features are present throughout the p-type films, however in n-type N-doped films high-density defect clusters are observed. These results suggest that the temperature under which ion implantation is performed plays a critical role in determining the amount of dynamic defect re- combination that can take place, as well as defect cluster formation processes. Ion implantation at elevated temperatures is shown to be an effective method to introduce increased concentrations of p-type N dopants while reducing the amount of stable post-implantation disorder. Finally, the fabrication and properties of p-type Ag-doped ZnO/n-type ZnO and p-type N-doped ZnO/n-type ZnO thin film junctions were reported. For the N-doped sample, a rectifying behavior was observed in the I-V curve, consistent with N-doped ZnO being p-type and forming a p-n junction. The turn-on voltage of the device was -2.3 V under forward bias. The Ag-doped samples did not result in rectifying behavior as a result of conversion of the p-type layer to n-type behavior under the n- type layer deposition conditions. The systematic studies in this dissertation provide possible routes to grow p-type Ag-doped ZnO films and in-situ thermal activation of N-implanted dopant ions, to overcome the growth temperature limits, and to push one step closer to the future integration of ZnO-based devices. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149354

Author: Hang Khume Tan
Publisher:
ISBN:
Category : Electric resistance
Languages : en
Pages : 125

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Author: David Winarski
Publisher:
ISBN:
Category : Oxide coating
Languages : en
Pages : 87

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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.

Author: Venkaiah Malapati
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659588426
Category :
Languages : en
Pages : 196

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ZnO based semiconductors as transparent electrodes have given wide range of applications in optoelectronic devices due to their wide band gap replacing the conventional GaN semiconductors. This book is the compilation of the work of Venkaiah Malapati which deals with the synthesis and characterization of an interesting room temperature undoped and 3d transition metal doped ZnO thin films by rf magnetron sputtering. this work addresses the following three major questions... (1) what is the effect of working gas pressure on the properties of undoped and Mn, Fe and Mn-Fe co-doped ZnO thin films. Here, the effect of argon and oxygen gas pressure studied undoped and Mn and Fe doped thin films studied. This book includes a systematic study of structure, morphology, optical, mechanical and magnetic properties of undoped Mn, Fe doped ZnO thin films studied. This book should be useful to readers in enhancing their knowledge about thin film preparation and their characterization.

Author: Xiang Liu
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Zinc oxide (ZnO) is a wide band gap semiconductor material. It is a promising candidate for short wavelength optoelectronic devices.

Author: Prasada Rao Talakonda
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659370106
Category :
Languages : en
Pages : 220

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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.

Author: Pankaj Jyoti Hazarika
Publisher: ProQuest
ISBN: 9780549319801
Category : Materials science
Languages : en
Pages :

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Diamond like carbon (DLC) films have gained grounds in the biomedical field as an inert, biocompatible, low friction and wear resistant coating and are widely used in heart valves, coronary artery stents, dental implants, knee prosthesis and other vascular devices. In addition, Ag nanoparticles/films can prevent the formation of biofilm on biomedical implants by degrading the metabolic activities like permeability and respiration and also impair DNA replicability. Thus, Ag-doped DLC (Ag-DLC) can serve as a multifunctional bio coating combining desirable antibacterial and physical/mechanical characteristics. In the present study, Ag-DLC films were synthesized utilizing a hybrid Plasma CVD and Magnetron sputtering process in a CH4/Ar glow discharge. Nanocomposite films containing Ag nanoparticles in an amorphous DLC matrix with various amounts of Ag were synthesized and characterized by Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS). Tribological experiments were performed to assess the frictional behavior and wear resistance of the Ag-DLC films as a function of Ag content. Anodic polarization experiments were conducted to characterize the electrochemical behavior of the Ag-DLC films. TEM results revealed that Ag nanoparticles of 4-7 nm in size were uniformly distributed in an amorphous DLC matrix. Microhardness of DLC films exhibited a hardness of 22 GPa and it gradually decreased with increasing Ag content in the films. Wear rate of DLC film was 1.9 x 10-8 mm3/Nm and it increased to 8 x 10-7 mm3/Nm for Ag-DLC (5% Ag) film. Electrochemical behavior experiments showed that Ag-DLC films exhibited an inert behavior compared to the pure silver.

Author: Usha Chandra
Publisher: BoD – Books on Demand
ISBN: 9535132458
Category : Science
Languages : en
Pages : 312

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Versatility, extended compositional ranges, better homogeneity, lesser energy consumption, and requirement of nonexpensive equipments have boosted the use of sol-gel process on top of the popularity in the synthesis of nanosystems. The sol-gel technique has not only revolutionized oxide ceramics industry and/or material science but has also extended widely into multidimensional applications. The book Recent Applications in Sol-Gel Synthesis comprises 14 chapters that deal mainly with the application-oriented aspects of the technique. Sol-gel prepared metal oxide (MO) nanostructures like nanospheres, nanorods, nanoflakes, nanotubes, and nanoribbons have been employed in biomedical applications involving drug deliveries, mimicking of natural bone, and antimicrobial activities. The possibility of controlling grain size in aerogel and preparation of ultrahigh-temperature ceramic (UHTC)-based materials, fluorescent glasses, ultraviolet photosensors, and photocatalysts have been discussed in detail by the experts in the field. The usefulness of sol-gel materials as active GRIN, as textile finisher, and as leather modifier with water-repellent and oil-resistive properties would be an incentive for researchers keen to pursue the field.

Author: Chennupati Jagadish
Publisher: Elsevier
ISBN: 0080464033
Category : Science
Languages : en
Pages : 600

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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