Nanowires belong to one dimensional nanostructure and can be defined as, the nanostructures have two confined dimensions in nanometer scale and other one is unconstrained direction for electrical conduction. In nanowires the surface to volume ratio of atoms increased. One dimensional nanowires are attracted towards potential application because these are used as building blocks for complex micro and nano devices. Zinc Oxide nanowires (ZnO NWs) have got an efficacious place in nanoworld due to their tremendous properties and applications. In present work, physical properties of the ZnO NWs have been modified by carbon (C) and phosphorus (P) ion implantation. This book reveals that phosphorous ions implantation in ZnO NWs is a successful approach towards the tailoring of P-type ZnO Nanowires.
Among oxide semiconductor nanomaterials, zinc oxide (ZnO) is the richest family of nanostructures and has versatile applications in electronic, photonic, photovoltaic, piezoelectric, and spintronic devices. Understanding the electrical, optical, thermal and mechanical properties and controlling the synthesis conditions of ZnO nanostructures are essential to achieve the aforementioned applications at the industrial level. This book presents an overview on the physical properties of ZnO. The synthesis of ZnO nanowires/nanorods on alumina and silicon substrates by a thermal evaporation method is discussed. The growth mechanisms, morphology, crystal structure and photoluminescent properties of the nanowires/nanorods have been analysed in detail.
The work focuses on the investigation of single Co-implanted ZnO nanowires using X-ray fluorescence (XRF), X-ray absorption spectroscopy (XAS), and X-ray diffraction (XRD) techniques with a nanometer resolution. The ZnO nanowires (NWs) were grown on Si substrates using VLS mechanism. The synthesized ZnO NWs were doped with Co via an ion implantation process. For the first time, the combined use of these techniques allows us to study the dopant homogeneity, composition, short- and large-range structural order of single NWs. The nano-XRF results indicate the successful and homogeneous Co doping with the desired concentrations in the ZnO NWs by an ion implantation process. The nano-XAS and XRD data analyses provide new insights into the lattice distortions produced by the structural defect formation generated by the ion implantation process. These findings highlight the importance of the post-implantation thermal annealing to recover the structure of single ZnO NWs at the nanometer length scale. In general, the methodologies used in this work open new avenues for the application of synchrotron based multi-techniques for detailed study of single semiconductor NWs at the nanoscale.
Extra application of magnetic nanowires and the importance of GMR phenomenon in magnet/non magnet nanowires attracted our interests to investigate the effects of pulse electrodeposition on magnetization decrease in alloy nanowires of CoCu in different copper concentration to achieve the optimum conditions to fabricate multilayer nanowires. In addition, saturation magnetization and coercivity field of alloy CoCu nanowires embedded in porous alumina template and the effect of annealing on magnetic properties were studied. Firstly, ordered nanopores were fabricated by two step mild anodization and then nanowires were grown inside them by pulse and ac electrodeposition methods. Also, the effects of electrodeposition and copper concentration on nanowires behavior were studied by scanning microscope(SPM)&(SEM), alternating gradient force magnetometer (AGFM), x-ray diffraction pattern (XRD)and EDS analysis.
Four typical kinds of crop seeds were studied as non-metallic bio-precursors to synthesize Biogenic Nitrogen-Phosphorous-codoped ZnO (BNP-ZnO). The as-prepared BNP-ZnO samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscope (FT-IR) and UV–Vis spectroscopy. The results show that the as-synthesized nanomaterials have pure hexagonal wurtzite structure. Also the crystalline formation of ZnO and the absorbed species on the nanocrystals were observed. In the experiments it was found that the absorption edges of BNP-ZnO were extended to visible light compared to synthesized ZnO. Furthermore, experiments of crystal violet (CV) degradation under sunlight irradiation indicate superior photocatalytic activity of BNP-ZnO, of which the degradation rate is almost four times that of synthesized ZnO.
This book focuses on fabrication of ZnO/CdS optical sensor. Nanocrystalline ZnO/CdS core-shell optical sensors were fabricated by chemical bath deposition (CBD) method. Vertically aligned ZnO nanorods were firstly synthesized on silicon p-type (111) by CBD method with assist of microwave. The CdS were deposited on the ZnO nanorods to create core-shell structure by using CBD method with cadmium chloride (CdCl2) 0.15M as Cd2+ ion source at difference deposition time. ZnO nanorods were the core and CdS were the shell of this core-shell structure. The photoconductive testing was carried out to test this optical sensor light detection by shining ultraviolet (UV) light pulse on the devices. The devices affect the light absorption and have higher sensitivity to the light. The highest sensitivity reached 53% for the ZnO/CdS optical sensor while the ZnO optical sensor only 6.77% and ZnO/CdS can response to high frequency light pulse. The energy band gap of ZnO/CdS was also lowered to 3.3eV compared to ZnO, 3.38eV. These results demonstrate the existence of CdS has enhanced the ability and the properties of optical sensor compared to ZnO nanorods optical sensor alone.
This book presents a clear and comprehensive coverage of the synthesis and characterization techniques of pure prepared semiconductor ZnO, doped ZnO and Modified ZnO nanoparticles which have potential applications in optoelectronics devices. Salient features involves: Synthesis and structural,optical characterization of pure and doped (Cu and Sb) ZnO nanoparticles. Synthesis and structural, optical characterization of modified ZnO nanoparticles using 2-aminothiols and 2-aminothiophenol as the capping agent for surface modification of ZnO nanoparticles. Possible optoelectronics application has been discussed by using modified ZnO nanoparticles for the realization of molecular AND gate.
This research describes the development of giant magnetoresistive (GMR) sensors with multilayered magnetic nanowires containing alternating ferromagnetic and nonmagnetic layers. Pulsed electrochemical deposition was used to control the periodic structure of multilayered nanoscale nanowires with preferential crystalline orientation. Co/Cu multilayered magnetic nanowires were grown through polymer nanopore membrane on substrates by lithography-assisted template bonding (LATB) method. Layer thicknesses and crystalline structure were varied and controlled to have an effect on the GMR results. Measurements and results of embedded GMR sensors in a prototype motor are also presented.
This book consists of synthesis and characterization of ZnO and Mn-doped ZnO ?nanoparticles for photocatalyst process. The work contains synthesis (co- precipitation), ?Characterization (TEM, SEM, EDX, FTIR, XRD, BET, UV-visible NIR) and ?application of ZnO and Mn-doped ZnO nanoparticles. The application included ?photodegradation of m-, o- and p-cresol that was carried out under UV and visible ?irradiation at room temperature, atmospheric pressure, and different PH by batch ?photoreactors. The intermediates were identified by UPLC and mineralization was ?confirmed by TOC measurement. As a result, 1%wt Mn-doped ZnO with lower ?particles size, higher surface area, high cresols adsorption, lower agglomerate, ?appropriate band gap and higher photodegradation ability than other % of Mn-doped ?ZnO is the best photocatalyst that may enhance the photocatalyst activity of ZnO ?under visible light.?
When dimensions of material approach nanoscale, they often reveal startling properties. These unique properties when compared to bulk material make them interesting candidates for new technologies. In a race to sustain Moore’s Law, silicon nanowires which possess remarkable properties diverse from bulk-silicon have gained notable attention. With advancement in technology engineers have mastered the art of fabrication of nanowires, but there exists a big gap in understanding various phenomena at this scale. The aim of this work is to bridge the gap and give an insight into some interesting properties and application of silicon nanowires. Using top-down lithography Silicon nanowires are fabricated and various mechanical and electrical properties are studied. The use of functionalized silicon nanowires for gas detection is demonstrated with very large sensitivity and detection window reported for the first time.
In this book,porous silicon preparing by electrochemical etching technique using different parameters such as silicon orientation ((100) & (111)), etching time (5, 10, 20 & 35 min), current density (10, 20, 30 & 40 mA/cm2) and HF concentration (15%, 20% & 30%). And next step of project was deposition of ZnO thin film on glass by spray pyrolysis technique from Zinc nitrite and study the effect of changing thickness of ZnO film (100, 200, 500 & 800 nm). And the final step of project consist deposition ZnO film on PS. The measurement refer that PS (100) gives the characteristics of nanoscale better than directional silicon (111) due to the crystal structure and the different in interaction between the HF electroyied and silicon. And The measurements of ZnO refer n-type semiconductor with hexagonal structure and the decreasing of ZnO thickness leads to increasing in energy gap due to decreasing in grain size. And when ZnO was deposited on PS the properties of both ZnO and PS will improved, like deceasing in crystal size and increasing in absorption of light with increasing in blue shift of PS and increasing in UV emission of ZnO film with incresing in rsistivty of heteojuntion
This book focuses on the characteristics of ZnO films fabricated by AP-MOCVD. ZnO shows high optical transmittance (greater than 85%) and electrical conductivity (resistivity about 10-4 ?-cm) for the transparent electrode. Particularly, compared to ITO, the material resource of ZnO is ample and no after-use worry concerned with the environmental protection is required. So this thesis has completed that the characterizations of undoped, n- and p-type ZnO semiconductors fabricated by AP-MOCVD.
Nanoparticles exhibit many interesting properties especially when it is less than 10 nanometer due to its quantum size effect. ZnO nanoparticles have abroad range of electronics, optical, piezoelectric applications due to its direct band gap . In this book it is synthesized in the quantum size by a solvothermal method which is characterized by easy procedure, easy control of particle radius and low coast of processing.Many applications of ZnO nanoparticles could be improved by changing the particle size, morphology and controlling the growth process. This work investigates the effect of temperature, growth period, surfactants and some additives on the particle size, rate constant and energy gap of ZnO nanoparticles. Understanding how these factors enhance or inhabit growth mechanism of ZnO nanoparticles will lead to produce specialized ZnO nanostructures which is important for device fabrication.
In this work we prepared Zinc oxide nano - particles controllably by polymeric precursor method. In this approach, zinc nitrate Zn (NO3)26H20 and polyvinyl-pyrolidine were used for the preparation of ZnO nanoparticles. The microstructure of the ZnO nano particles were characterized by X-ray diffractometer and Scanning electron microscopy and the optical property was investigated by the room temperature UV-Visible spectra. Zinc oxide (ZnO), a versatile material, has been attracting attention. It has been proved as a potential agent for seed germination activity. In the application part we dealt the seed growth activity for Cicerarieitnum seeds with ZnO nanoparticles. In this we observed growth is rapid for seeds washed with ZnO nanoparticles.