Download or read book An Investigation of the Electrical Properties of Zinc Oxide Thin Films Influenced by Oxygen Adsorption written by James Chi-Te Yen and published by . This book was released on 1973 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of the Performance and Stability of Zinc Oxide Thin film Transistors and the Role of High k Dielectrics written by Ngwashi Divine Khan and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Transparent oxide semiconducting films have continued to receive considerable attention, from a fundamental and application-based point of view, primarily because of their useful fundamental properties. Of particular interest is zinc oxide (ZnO), an n-type semiconductor that exhibits excellent optical, electrical, catalytic and gas-sensing properties, and has many applications in various fields. In this work, thin film transistor (TFT) arrays based on ZnO have been prepared by reactive radio frequency (RF) magnetron sputtering. Prior to the TFT fabrication, ZnO layers were sputtered on to glass and silicon substrates, and the deposition parameters optimised for electrical resistivities suitable for TFT applications. The sputtering process was carried out at room temperature with no intentional heating. The aim of this work is to prepare ZnO thin films with stable semiconducting electrical properties to be used as the active channel in TFTs; and to understand the role of intrinsic point defects in device performance and stability. The effect of oxygen (O2) adsorption on TFT device characteristics is also investigated. The structural quality of the material (defect type and concentration), electrical and optical properties (transmission/absorption) of semiconductor materials are usually closely correlated. Using the Vienna ab-initio simulation package (VASP), it is predicted that O2 adsorption may influence film transport properties only within a few atomic layers beneath the adsorption site. These findings were exploited to deposit thin films that are relatively stable in atmospheric ambient with improved TFT applications. TFTs incorporating the optimised layer were fabricated and demonstrated very impressive performance metrics, with effective channel mobilities as high as 30 cm2/V-1s-1, on-off current ratios of 107 and sub-threshold slopes of 0.9? 3.2 V/dec. These were found to be dependent on film thickness (~15? 60 nm) and the underlying dielectric (silicon dioxide (SiO2), gadolinium oxide (Gd2O3), yttrium oxide (Y2O3) and hafnium oxide (HfO2)). In this work, prior to sputtering the ZnO layer (using a ZnO target of 99.999 % purity), the sputtering chamber was evacuated to a base pressure ~4 x 10-6 Torr. Oxygen (O2) and argon (Ar) gas (with O2/Ar ratio of varying proportions) were then pumped into the chamber and the deposition process optimised by varying the RF power between 25 and 500 W and the O2/Ar ratio between 0.010 to 0.375. A two-level factorial design technique was implemented to test specific parameter combinations (i.e. RF power and O2/Ar ratio) and then statistical analysis was utilised to map out the responses. The ZnO films were sputtered on glass and silicon substrates for transparency and resistivity measurements, and TFT fabrication respectively. For TFT device fabrication, ZnO films were deposited onto thermally-grown silicon dioxide (SiO2) or a high-k dielectric layer (HfO2, Gd2O3 and Y2O3) deposited by a metal-organic chemical deposition (MOCVD) process. Also, by using ab initio simulation as implemented in the?Vienna ab initio simulation package (VASP)?, the role of oxygen adsorption on the electrical stability of ZnO thin film is also investigated. The results indicate that O2 adsorption on ZnO layers could modify both the electronic density of states in the vicinity of the Fermi level and the band gap of the film. This study is complemented by studying the effects of low temperature annealing in air on the properties of ZnO films. It is speculated that O2 adsorption/desorption at low temperatures (150? 350 0C) induces variations in the electrical resistance, band gap and Urbach energy of the film, consistent with the trends predicted from DFT results.

Download or read book Zinc Oxide A Material for Micro and Optoelectronic Applications written by Norbert H. Nickel and published by Springer Science & Business Media. This book was released on 2005-12-28 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, a significant effort has been devoted to the investigation of ZnO as a suitable semiconductor for UV light-emitting diodes, lasers, and detectors and hetero-substrates for GaN. Research is driven not only by the technological requirements of state-of-the-art applications but also by the lack of a fundamental understanding of growth processes, the role of intrinsic defects and dopants, and the properties of hydrogen. The NATO Advanced Research Workshop on “Zinc oxide as a material for micro- and optoelectronic applications”, held from June 23 to June 25 2004 in St. Petersburg, Russia, was organized accordingly and started with the growth of ZnO. A variety of growth methods for bulk and layer growth were discussed. These techniques comprised growth methods such as closed space vapor transport (CSVT), metal-organic chemical vapor deposition, reactive ion sputtering, and pulsed laser deposition. From a structural point of view using these growth techniques ZnO can be fabricated ranging from single crystalline bulk material to polycrystalline ZnO and nanowhiskers. A major aspect of the ZnO growth is doping. n-type doping is relatively easy to accomplish with elements such al Al or Ga. At room temperature single crystal ZnO exhibits a resistivity of about 0. 3 -cm, an electron mobility of 2 17 -3 225 cm /Vs, and a carrier concentration of 10 cm . In n-type ZnO two shallow donors are observable with activation energies of 30 – 40 meV and 60 – 70 meV.

Download or read book Transparent Conductive Zinc Oxide written by Klaus Ellmer and published by Springer Science & Business Media. This book was released on 2007-12-29 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) belongs to the class of transparent conducting oxides that can be used as transparent electrodes in electronic devices or heated windows. In this book the material properties of, the deposition technologies for, and applications of zinc oxide in thin film solar cells are described in a comprehensive manner. Structural, morphological, optical and electronic properties of ZnO are treated in this review.

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 Investigation of the Electrical Properties of Thin Oxide Films by the Gaseous Discharge Plasma Method written by S. S. Gutin and published by . This book was released on 195? with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Zinc Oxide written by Hadis Morkoç and published by John Wiley & Sons. This book was released on 2008-12-03 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first systematic, authoritative and thorough treatment in one comprehensive volume presents the fundamentals and technologies of the topic, elucidating all aspects of ZnO materials and devices. Following an introduction, the authors look at the general properties of ZnO, as well as its growth, optical processes, doping and ZnO-based dilute magnetic semiconductors. Concluding sections treat bandgap engineering, processing and ZnO nanostructures and nanodevices. Of interest to device engineers, physicists, and semiconductor and solid state scientists in general.

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1984 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Technical Translations written by and published by . This book was released on 1962 with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 868 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Processing and Characterization of P Type Doped Zinc Oxide Thin Films written by Michelle Anne Myers and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Digest of Literature on Dielectrics written by and published by National Academies. This book was released on 1978 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Investigation of the Oxygen Pressure Dependence of the Electrical Properties of Sintered Zinc Oxide at High Temperatures written by Charles Frederick Wahlig and published by . This book was released on 1953 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Optical and Electrical Properties of Pure and Doped Zinc Oxide Films by RF Sputtering Method written by 賴豊文 and published by . This book was released on 2009 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1989 with total page 1116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of 17th Edition of International Conference on Emerging Trends in Materials Science and Nanotechnology 2018 written by EuroScicon and published by EuroScicon. This book was released on 2018-04-20 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: April 26-27, 2018 Rome, Italy Key Topics : Nano Electronics, Nanotechnology For Clean Energy And Environment, Nano Applications, Nano Biotechnology, Nano Bio Medicine, Carbon And Graphene Nano-Structures, Polymer Science Engineering, Bio Polymers And Bio Plastics, Advanced Materials Science, Nano Composites, Nano Technology In Materials Science, Corrosion Engineering And Corrosion Protection, Biomaterials, Electronic, Optical & Magnetic Materials., Nano Photonics, Advanced Nano Materials,