Download or read book Growth and Optoelectronic Properties of Al doped ZnO Nanowire written by 張竣榮 and published by . This book was released on 2012 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydrothermal Synthesis of Al doped ZnO Nanowires and Their Application for Photovoltaic Devices written by Hyoungwon Park and published by . This book was released on 2014 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor nanostructures exhibit distinct properties by virtue of nano-scale dimensionality, resulting in recent interest in semiconducting nanowires for electronic, photonic, and energy applications. Along with nanowires, quantum dots are solution-processable nanocrystals with tunable band gap energies as a function of their size. Based on all of these promising properties that nanostructures exhibit, nanowires and quantum dots are excellent candidates for next-generation optoelectronic devices, including solar cells and light-emitting diodes. However, the realization of nanostructured materials for solar cell device applications is limited by the fundamental trade-off between light absorption and photocarrier collection. Vertically aligned ZnO nanowire arrays can decouple absorption and collection by acting as highly-conductive channels for extracting photogenerated electrons from deep within the film. This thesis illustrates a scheme for the development of ordered bulk heterojunction photovoltaic devices incorporating solution-based n-type doped ZnO nanowires and PbS quantum dots. In order to improve the electrical properties of ZnO nanowires, Al doping of hydrothermally synthesized ZnO nanowires is studied along with the optimization of doping concentration. The morphology of ZnO nanowire arrays is also studied as a function of the doping concentration in the growth solution. Finally, photovoltaic devices are fabricated and the effect of Al-doping of ZnO nanowires is investigated by device characterization techniques.

Download or read book Handbook of Nanoelectrochemistry written by Mahmood Aliofkhazraei and published by Springer. This book was released on 2015-11-03 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edited book is devoted to different electrochemical aspects of nano materials. This comprehensive reference text is basically divided in 3 parts: electrochemical synthesis routes for nanosized materials, electrochemical properties of nano materials and electrochemical characterization methods for nanostructures. The Handbook is a reference work to chemists and materials scientists interested in the nano aspects of electrochemistry. The chapters are written by a number of international experts in the field and the content will assist members of both electrochemical and materials communities to keep abreast of developments in the field.

Download or read book Fundamental Understanding of the Growth Doping and Characterization of Aligned ZNO Nanowires written by Gang Shen and published by . This book was released on 2014 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) is a II-VI semiconductor whose wide direct bandgap (3.37 eV) and large exciton binding energy (60 meV) make it compelling for optoelectronic devices such as light emitting diodes, lasers, photodetectors, solar cells, and mechanical energy harvesting devices. One dimensional structures of ZnO (nanowires) have become significant due to their unique physical properties arising from quantum confinement, and they are ideal for studying transport mechanisms in one-dimensional systems. In this doctoral research work, ZnO nanowire (NW) arrays were synthesized on sapphire substrates through carbo-thermal reduction of ZnO powders, and the effects of growth parameters on the properties of ZnO NW arrays were studied by scanning and transmission electron microscopy, X-ray diffraction, photoluminescence and Raman spectroscopy. Based on the phonon mode selection rules in wurtzite ZnO, confocal Raman spectroscopy was used to assess the alignment of ZnO NWs in an array, thereby complementing X-ray diffraction. Al doped ZnO NW arrays were achieved by mixing Al powder into the ZnO and graphite source mixture, and the presence of Al was confirmed by Energy-dispersive X-ray spectroscopy. The incorporation of Al had the effects of lowering the electrical resistivity, slightly deteriorating crystal quality and suppressing defect related green emission. Two models of ZnO NW growth were developed by establishing the relationship between NW length and diameter for undoped and Al doped ZnO NWs separately. The growth of undoped ZnO NWs followed the diffusion-induced model which was characterized by thin wires being longer than thick wires, while the growth of Al doped ZnO was controlled by Gibbs-Thomson effect which was characterized by thin wires being shorter than thin wires. Local electrode atom probe analysis of ZnO NWs was carried out to study the crystal stoichiometry and Al incorporation. Undoped ZnO NWs were found to be high purity with no detectable impurities. Possible Al incorporation related peaks were observed in the mass spectrum of Al doped ZnO NWs. Further work on Al doped ZnO LEAP analysis is needed to better understand the Al dopant.

Download or read book Electrochemical Growth and Characterization of ZnO Nanowires written by Lilei Hu and published by . This book was released on 2014 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: ZnO semiconductor materials, especially nanostructured materials, have potential applications in large-area electronics, photonics and optoelectronics due to their unique electrical and optical properties. ZnO nanowires have advantages of high surface area to volume ratio, with the prospective for nanoscale control of doping the electrical properties for 1-D nanoelectronic devices. Many techniques have been tried to achieve high quality ZnO nanowires in large scale with low cost and simple fabrication. However, most of these techniques require high temperatures that exclude applications in flexible electronics. P-type conductivity is another impediment for fully realizing ZnO materials for electronic device application; and this limitation has prevented advances in optoelectronic and integrated circuit applications for ZnO. To overcome the problems, this study investigated the synthesis and doping of ZnO nanowires at low temperature through a rapid electrochemical deposition growth technique. Material properties were studied using scanning electron microscopy (SEM), photoluminescence spectroscopy (PL), Raman spectroscopy, X-ray diffraction (XRD), ultraviolet to visible (UV-Vis) transmission spectroscopy, and electrical current-voltage measurements. ZnO nanowire doping was investigated using Al for n-type doping and for p-type doping, Ag/Al (co-doping) and Li. Al and Ag have significant influences on ZnO nanowire structures, while Li was found to improve the nanowire structure quality. The mechanisms for electrochemical deposition were studied through characterization of the chemical reactions, interface science and semiconductor/solution interface. It was found that the low temperature grown nanowires had high oxygen vacancy condition induced donor defect states, while, incorporation of Li dopants contributed to trap states (deep acceptor states), rather than shallow acceptor states in the band gap. Shown by XRD and PL, oxygen assisted post-growth annealing was found to promote recrystallization of ZnO and elimination of oxygen vacancies for better crystal quality and photoluminescence emission. Cr, Al or Au metals were used as contacts to Li-doped ZnO nanowires to examine electrical properties of the doped nanowires, turning out high ideal factor were obtained because of the poor contact quality due to significant surface and interface states in ZnO nanowires. At last, mechanisms of surface states related tunneling current at the metal-semiconductor interface were discussed.

Download or read book Toward the Optimization of Low temperature Solution based Synthesis of ZnO Nanostructures for Device Applications written by Hatim Alnoor and published by Linköping University Electronic Press. This book was released on 2017-10-06 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: One-dimensional (1D) nanostructures (NSs) of Zinc Oxide (ZnO) such as nanorods (NRs) have recently attracted considerable research attention due to their potential for the development of optoelectronic devices such as ultraviolet (UV) photodetectors and light-emitting diodes (LEDs). The potential of ZnO NRs in all these applications, however, would require synthesis of high crystal quality ZnO NRs with precise control over the optical and electronic properties. It is known that the optical and electronic properties of ZnO NRs are mostly influenced by the presence of native (intrinsic) and impurities (extrinsic) defects. Therefore, understanding the nature of these intrinsic and extrinsic defects and their spatial distribution is critical for optimizing the optical and electronic properties of ZnO NRs. However, identifying the origin of such defects is a complicated matter, especially for NSs, where the information on anisotropy is usually lost due to the lack of coherent orientation. Thus, the aim of this thesis is towards the optimization of the lowtemperature solution-based synthesis of ZnO NRs for device applications. In this connection, we first started with investigating the effect of the precursor solution stirring durations on the deep level defects concentration and their spatial distribution along the ZnO NRs. Then, by choosing the optimal stirring time, we studied the influence of ZnO seeding layer precursor’s types, and its molar ratios on the density of interface defects. The findings of these investigations were used to demonstrate ZnO NRs-based heterojunction LEDs. The ability to tune the point defects along the NRs enabled us further to incorporate cobalt (Co) ions into the ZnO NRs crystal lattice, where these ions could occupy the vacancies or interstitial defects through substitutional or interstitial doping. Following this, high crystal quality vertically welloriented ZnO NRs have been demonstrated by incorporating a small amount of Co into the ZnO crystal lattice. Finally, the influence of Co ions incorporation on the reduction of core-defects (CDs) in ZnO NRs was systematically examined using electron paramagnetic resonance (EPR).

Download or read book Zinc Oxide Nanowire Array based Optoelectronic Devices written by Guoping Wang and published by . This book was released on 2011 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: ZnO nanowire array-based optoelectronic devices are discussed in this dissertation. ZnO has a wide band gap of 3.37 eV and a large exciton binding energy of 60 meV at room temperature, which make it a promising candidate for optoelectronic devices such as blue-light emitting diodes, ultraviolet laser diodes and photodiodes. Recently, there have been tremendous interests in ZnO nanowire arrays. It is well known that one of the biggest challenges toward good ZnO-based optoelectronic devices is the difficulty of reliably fabricating p-type ZnO due to the self-compensating effect from native defects (for example, oxygen vacancy V o and zinc interstitial Zni) and/or H incorporation. There has already been a great deal of efforts on the fabrication of p-type ZnO films by doping group I (Na, Ag) and group V elements (N, P, As, Sb) as p-type dopants. In contrast, there have been only a few reports on p-type ZnO nanowires (doped with N, P and Na). Recently, researchers are interested in developing optoelectronic devices based on ZnO nanowires such as biosensors, ultraviolet detectors, ultraviolet light emitting diodes and electrically driven nanowire lasers. The growth of p-type ZnO nanowires with good stability will be an essential step for the applications of nanowires in nanoelectronics and optoelectronics. In this dissertation, first, n-type ZnO nanowire array and its application have been discussed. ZnO has very high electronic carrier mobility and electron affinity, making it a very possible candidate as an effective dye-sensitized solar cell (DSSC) semiconductor. The great properties of vertically aligned ZnO-nanowire array, such as large surface area and fast electron-transport rate, make it a very promising option for the photoanode of DSSCs. Nanowires provide electrons injected from optically excited dye a direct effective path to collecting electrode via the semiconductor conduction band, offering the potential for much faster charge transport than nanoparticle cells. In order to make homojunctional devices based on ZnO nanowire, a great deal of efforts has been made on the growth of p-type ZnO nanowire. Ag, a group Ib element, was predicted to be an acceptor in ZnO when incorporated into substitutional Zn sites and researchers experimentally demonstrated reliable fabrication of p-type ZnO thin films doped with Ag on sapphire substrate and also demonstrated the possibility of achieving Ag-doped p-type ZnO nanowires. Also Sb as an effective dopant for reproducible p-type ZnO thin films has been shown in our group. In chapter 3 of this dissertation, the synthesis and characterization of single-crystalline Ag-doped p-type ZnO nanowires and also Sb-doped p-type ZnO nanowire arrays have been discussed. In chapter 4 of this dissertation, ZnO homojunction photodiodes based on Sb-doped p-type nanowire array have been discussed. In chapter 5 of this dissertation, LED devices based on Sb-doped p-type nanowire array have been discussed. In chapter 6 of this dissertation, electrically pumped ZnO nanowirewaveguided lasing based on Sb-doped p-type nanowire array has been discussed. In chapter 7, the gain calculation for ZnO has been made and a brief discussion about the comparison between the calculation results and the experimental results has also been made. In chapter 8, Lists of conclusions are made for this dissertation.

Download or read book The Crystallized Mechanism and Optoelectronic Properties of Sol gel Synthesized Doped ZnO Nanowires Thin Film written by 陳冠仁 and published by . This book was released on 2010 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Nanomaterials Properties written by Bharat Bhushan and published by Springer Science & Business Media. This book was released on 2014-03-13 with total page 1467 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanomaterials attract tremendous attention in recent researches. Although extensive research has been done in this field it still lacks a comprehensive reference work that presents data on properties of different Nanomaterials. This Handbook of Nanomaterials Properties will be the first single reference work that brings together the various properties with wide breadth and scope.

Download or read book Zinc Oxide Bulk Thin Films and Nanostructures Processing Properties and Applications written by Chennupati Jagadish and published by Elsevier Science. This book was released on 2006-09 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 Semiconductor Nanostructures for Optoelectronic Applications written by Todd D. Steiner and published by Artech House. This book was released on 2004 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Tiny structures measurable on the nanometer scale (one-billionth of a meter) are known as nanostructures, and nanotechnology is the emerging application of these nanostructures into useful nanoscale devices. As we enter the 21st century, more and more professional are using nanotechnology to create semiconductors for a variety of applications, including communications, information technology, medical, and transportation devices. Written by today's best researchers of semiconductor nanostructures, this cutting-edge resource provides a snapshot of this exciting and fast-changing field. The book covers the latest advances in nanotechnology and discusses the applications of nanostructures to optoelectronics, photonics, and electronics.

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 ZnO Nanostructure Synthesis Laser Direct Writing Process for Optoelectronic Devices written by DAEHO LEE and published by . This book was released on 2012 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) has a long history of usage in electronics. Recently, ZnO has been gathering great interest of researchers in nanoscience due to its diverse and versatile morphologies such as nanoparticles (NP), nanowires (NW), nanorods, nanotubes, nanohelixes, etc. This dissertation deals with studies covering from the synthesis of ZnO nanostructures to deposition & patterning methods and their applications for optoelectronic devices such as transparent electrodes, active layers for thin film transistor and photovoltaics. A very well-dispersed, transparent and concentration-tunable ZnO NP solution was successfully synthesized with a new process. Highly transparent ZnO thin films were fabricated by spin coating and subsequent ultra short-pulsed UV laser annealing was performed to change the film properties. While as-deposited NP thin films were not electrically conductive, laser annealing imparted a substantial conductivity increase. Thus, selective annealing for conductive patterns directly on the NP thin film without a photolithographic process was achieved. The conductivity is by a factor of 105 higher than that of the previously reported furnace-annealed ZnO NP films and even comparable to that of vacuum-deposited, impurity-doped ZnO films within a factor of 10. The ZnO film obtained from the process developed in this work has been applied to the fabrication of a thin film transistor (TFT) showing enhanced performance compared with the TFT fabricated on furnace annealed ZnO film. The ZnO TFT performance test reveals that by just changing the laser annealing parameters the solution-deposited ZnO thin film properties can be tuned suitable for both transparent conductors and semiconductor active layers. Two kinds of nanomaterial patterning methods via direct writing have been demonstrated. First, laser-assisted nanoimprinting of metal and semiconductor nanoparticles has been presented as a large area one step patterning method. With the method, submicron structures including mesh, line, nanopillar and nanowire arrays were fabricated on various kinds of wafer scale substrates. Using the rapid laser-based nanolithography, the prohibitive constraints of e-beam patterning could be overcome. Therefore, this method opens a way to the fabrication of electronic and energy devices with high throughput and ultra low-cost. Second, a drop on demand (DOD) inkjet printing of ZnO seed layers integrated with a CAD (computer aided design) system for a fully digital selective ZnO NW array growth has been discussed. Through proper natural convection suppression during the hydrothermal growth, successful ZnO nanowire local growth could be achieved. Without any need for the photolithographic process or stamp preparation, the NW growth location can be easily modified with high degree of freedom. These two methods are compatible with flexible plastic substrates. As an application of ZnO nanostructures for high efficiency solar cells, ZnO dye-sensitized solar cells (DSSCs) with greatly enhanced surface area for higher dye loading and light harvesting were demonstrated. The selective growth of "nanoforests" composed of high density, long branched tree-like multi generation hierarchical ZnO nanowire photoanodes by utilizing seed particles and a capping polymer increased the energy conversion efficiency significantly. The overall light-conversion efficiency of the branched ZnO nanowire DSSCs was almost 5 times higher than the efficiency of DSSCs constructed by upstanding ZnO nanowires. A parametric study to determine the optimum hierarchical ZnO nanowire photoanode was performed through the combination of both length-wise and branched growth processes.

Download or read book Zinc Oxide Nanostructures written by Magnus Willander and published by CRC Press. This book was released on 2014-07-22 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) in its nanostructured form is emerging as a promising material with great potential for the development of many smart electronic devices. This book presents up-to-date information about various synthesis methods to obtain device-quality ZnO nanostructures. It describes both high-temperature (over 100 C) and low-temperature (under

Download or read book Handbook of Zinc Oxide and Related Materials written by Zhe Chuan Feng and published by CRC Press. This book was released on 2012-09-26 with total page 565 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 Metal Oxides for Next generation Optoelectronic Photonic and Photovoltaic Applications written by Vijay Kumar and published by Elsevier. This book was released on 2023-09-15 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxides for Next Generation Optoelectronic, Photonic and Photovoltaic Applications focuses on the optoelectronic, photonic and photovoltaic behaviors of metallic oxides and closely related phenomena, from elementary principles to the latest findings. Each chapter includes a comprehensive evaluation of the synthesis and characterization of the most relevant metal oxides nanostructures for each application. In addition, there is a focus on methods to tune the materials’ properties in order to improve devices performance. This book is suitable for researchers and practitioners in academia and industry working in the disciplines of materials science and engineering, chemistry and physics. Metal oxides are widely used in various optoelectronic devices, photonics, display devices, smart windows, sensors, optical components, energy-saving, and harvesting devices. Each application requires materials with their own specific properties. By controlling the particle size, shape, crystal structure, one can tune various properties of metal oxides viz. bandgap, absorption properties, conductivity, which alter the material for the specific application. Includes discussions of synthesis and characterization of metal oxides materials for applications in next-generation optoelectronic, photonic and photovoltaic devices Emphasizes material design strategies of metal oxide nanostructures Focuses on the optoelectronic, photonic and photovoltaic behaviors of metallic oxides and closely related phenomena, from elementary principles to the latest findings

Download or read book Functional Nanostructures for Sensors Optoelectronic Devices and Drug Delivery written by Maria Angela Castriciano and published by MDPI. This book was released on 2020-12-04 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoparticles and nanostructured materials represent an active area of research and impact in many application fields. The recent progress obtained in the synthesis of nanomaterials, and the fundamental understanding of their properties, has driven significant advances for their technological applications. The Special Issue “Functional Nanostructures for Sensors, Optoelectronic Devices and Drug Delivery” aims to provide an overview of the current research activities in the field of nanostructured materials with a particular emphasis on their potential applications for sensors, optoelectronic devices and biomedical systems. The Special Issue includes submission of original research articles and comprehensive reviews that demonstrated or summarized significant advances in the above-mentioned research fields. The Special Issue is made up of fifteen original research articles and three comprehensive reviews covering various topics of nanostructured materials and relative characterization from fundamental research to technological applications. More than 100 scientists from universities and research institutions lent their expertize and shared their research activities to ensure the success of this Special Issue.