Готові списки джерел за темами / ZnO nanocrystal

Добірка наукової літератури з теми "ZnO nanocrystal"

Автор: Grafiati
Опубліковано: 14 березня 2023

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Статті в журналах з теми "ZnO nanocrystal"

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Della Gaspera, Enrico, Noel W. Duffy, Joel van Embden, Lynne Waddington, Laure Bourgeois, Jacek J. Jasieniak, and Anthony S. R. Chesman. "Plasmonic Ge-doped ZnO nanocrystals." Chemical Communications 51, no. 62 (2015): 12369–72. http://dx.doi.org/10.1039/c5cc02429c.

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2

Long, Mei, Huan Yuan, Ping Sun, Lei Su, and Xiangping Jiang. "UV-Assisted Room Temperature Gas Sensing with ZnO-Ag Heterostructure Nanocrystals Studied by Photoluminescence." Journal of Nanoscience and Nanotechnology 21, no. 9 (September 1, 2021): 4865–69. http://dx.doi.org/10.1166/jnn.2021.19121.

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Анотація:
Noble metal-metal oxide nanohybrids play a significant contribution in gas sensing applications at room temperature. Here, Ag-loaded ZnO with different Ag doping concentration are prepared by two-step polymer-network gel method, and NO2 sensing characteristics are tested at room temperature with various concentrations. The nanocrystal sizes are found to be more uniform with increasing with Ag concentration, and photoluminescence spectroscopy further reveals the different defects in ZnO–Ag nanocrystal lattices: pure ZnO has the largest intensity of the conduction band to valence band combination, and ZnO–Ag-1 (1 mol% Ag doping concentration) has the largest oxygen vacancy content, while ZnO–Ag-3 (3 mol% Ag doping concentration) has the largest excess zinc interstitial. It is showed that the gas sensing properties are independent of the size of nanocrystals, and more dependent on the nanocrystal defect structure. In this work, a new sensing mechanism is proposed according to the experimental results.
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3

LI, JUN, KUI ZHAO, RUOKUN JIA, YANMEI LIU, YUBAI BAI, and TIEJIN LI. "USING EMISSION QUENCHING TO STUDY THE INTERACTION BETWEEN ZnO NANOCRYSTALS AND ORGANIC LIGANDS." International Journal of Nanoscience 01, no. 05n06 (October 2002): 743–47. http://dx.doi.org/10.1142/s0219581x02000991.

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Анотація:
Colloidal ZnO nanocrystals with strong green luminescence were prepared. When ZnO nanocrystals were modified with different organic ligands, the emission quenching was measured and used to study the interaction between ZnO nanocrystal and organic ligands. Efficiency of emission quenching relates to the chemical structures of the ligands, and metal-thiolate bond was formed between nanocrystals and thiol ligands. The relative strength of the binding and the surface concentration of the adsorbed species could be determined using this method.
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4

Okazaki, K., T. Shimogaki, M. Higashihata, D. Nakamura, and T. Okada. "Synthesis and Nano-Processing of ZnO Nano-Crystals for Controlled Laser Action." MRS Proceedings 1439 (2012): 121–26. http://dx.doi.org/10.1557/opl.2012.1155.

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ABSTRACTLasing characteristics of a single Zinc oxide (ZnO) nanosheet and a single ZnO nanowire were investigated by an ultraviolet light excitation. ZnO nanocrystals were synthesized by chemical vapor deposition (CVD) method, and those ZnO nanocrystals were excited by a third-harmonic Q-switched Nd:YAG laser beam (355 nm, 5 ns). The emission spectra from a single ZnO nanocrystal was collected by an objective lens with a magnification factor of 100 or 50, coupled with a spectrometer with a light fiber. The area observed by the spectrometer is about 10 μm in diameter, and therefore the emission spectra from a single ZnO nanocrystal can be observed. The emission spectra showed the obvious lasing characteristics having mode structure and a threshold for lasing. The lasing threshold power density of a ZnO nanosheet and a ZnO nanowire were measured to be about 60 kW/cm2 and 150 kW/cm2, respectively. ZnO nanosheet can be a superior laser medium due to the lower threshold for lasing compared to the threshold of the ZnO nanowire. However, since the lasing spectra had mode structure, a single-longitudinal mode lasing would be required for a practical application. The single longitudinal mode lasing can be realized by a nanomachining of a grating on the ZnO nanocrystal surface due to distributed bragg reflector (DBR) laser. The minimum DBR pitch was estimated to be about 81 nm, which can be machined by focused-ion beam (FIB) focused up to 7 nm at minimum, and therefore, we demonstrated the nanomachining on a single ZnO nanowire. However, the single-longitudinal mode lasing was not observed so far, and thus optimization of experimental conditions such as the DBR pitch, ion dose amount and increasing the number of repetition of DBR would be required.
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ABDULSATTAR, MUDAR AHMED, and HASAN MUDAR ALMAROOF. "ADSORPTION OF H2 AND O2 GASES ON ZnO WURTZOID NANOCRYSTALS: A DFT STUDY." Surface Review and Letters 24, Supp01 (October 31, 2017): 1850008. http://dx.doi.org/10.1142/s0218625x18500087.

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Анотація:
In the present work, we apply wurtzoids nanocrystals with density functional theory to explain the sensitivity of ZnO nanostructures towards hydrogen and oxygen molecules. Present results of ZnO nanocrystals’ sensing to H2 and O2 molecules show a reduction in the energy gap and hence electrical resistivity of ZnO nanocrystals upon attachments of these molecules in agreement with experiment. The results also show that higher temperatures increase the sensitivity of ZnO wurtzoids towards H2 and O2 molecules with the maximum sensitivity approximately at 390[Formula: see text]C and 417[Formula: see text]C for H2 and O2 molecules, respectively, after which it begins to decline according to calculated Gibbs free energy. These temperatures are comparable with experimentally reported operating temperatures of 325[Formula: see text]C and 350[Formula: see text]C for the two gases, respectively. The main reaction mechanism is the dissociation of H2 or O2 molecules on ZnO nanocrystal surface in which hydrogen and oxygen atoms are attached to neighboring Zn and O surface atoms. The removal of these molecules from the surface is also performed by the formation of H2 and O2 molecules prior to their removal from the ZnO nanocrystal surface. Electronic charge transfers to the adsorbed atoms and molecules confirm and illustrate the mechanism mentioned above.
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6

Zhou, Dongming, and Kevin R. Kittilstved. "Control over Fe3+ speciation in colloidal ZnO nanocrystals." Journal of Materials Chemistry C 3, no. 17 (2015): 4352–58. http://dx.doi.org/10.1039/c5tc00470e.

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Анотація:
The ground state electronic structure of Fe3+ dopants in colloidal ZnO nanocrystals is studied by EPR spectroscopy and reveals multiple Fe3+ coordination environments during nanocrystal growth.
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7

Chen, Yi Chuan, Yue Hui Hu, Xiao Hua Zhang, Feng Yang, Hai Jun Xu, Xin Hua Chen, and Jun Chen. "Structure and Properties of Doped ZnO Nanopowders Synthesized by Methanol Alcoholysis Method." Advanced Materials Research 287-290 (July 2011): 1406–11. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1406.

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Анотація:
Pured ZnO, Al doped ZnO and Al-In co-doped ZnO nanopowders were synthesized by the methanol alcoholysis method at 130 °C. Structure, morphology and optical properties of ZnO nanopowders were characterized using X-ray diffraction, Transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and Photoluminescence (PL) spectra. The results show that ZnO nanopowders can be obtained in methanol solution at low temperature (130 °C). TEM images show that Al doped ZnO nanocrystals grow along the [002] axis quicker than other axes. FTIR spectra show that ZnO nanocrystals synthesized by the methanol alcoholysis include a little organic impurity. PL spectrums reveal that pure ZnO and doped ZnO nanocrystals have a blue band emission at 440 nm and a green band emission at 520 nm and 530 nm, respectively. Compared with the pure ZnO nanocrystal, the Al doping improves the luminescent properties.
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8

SRIVASTAVA, ANURAG, and NEHA TYAGI. "PRESSURE INDUCED PHASE TRANSITION AND ELECTRONIC PROPERTIES OF 1D ZnO NANOCRYSTAL: AN AB INITIO STUDY." International Journal of Nanoscience 11, no. 05 (October 2012): 1250035. http://dx.doi.org/10.1142/s0219581x12500354.

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Анотація:
We have analyzed the one-dimensional (1D) ZnO nanocrystals in its wurtzite (B4); zinc-blende (B3) and rocksalt (B1) type phases, by means of density functional theory (DFT) calculations. The energetic stability of nanocrystal has been analyzed using Revised Perdew–Burke–Ernzerhof (revPBE) type parameterized GGA potential. The B3 type phase is most stable amongst other phases of nanocrystals. The computation of ground state properties for all the phases of ZnO nanocrystals finds that the bulk modulus are smaller than their bulk counterpart, in turn softening the material at reduced dimensions. The electronic band structure analysis confirms the semiconducting nature of B4 type phase whereas other two are metallic.
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Champouret, Yohan, Grégory Spataro, Yannick Coppel, Fabienne Gauffre, and Myrtil L. Kahn. "Nanocrystal–ligand interactions deciphered: the influence of HSAB and pKa in the case of luminescent ZnO." Nanoscale Advances 2, no. 3 (2020): 1046–53. http://dx.doi.org/10.1039/c9na00769e.

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Анотація:
The pKa values of an organic substrate determines its interaction with the nanocrystal's surface while its hard or soft character will govern the emission intensity of the ZnO nanocrystals.
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10

Bai, Rekha, Dinesh K. Pandya, Sujeet Chaudhary, Veer Dhaka, Vladislav Khayrudinov, Jori Lemettinen, Christoffer Kauppinen, and Harri Lipsanen. "Site-specific growth of oriented ZnO nanocrystal arrays." Beilstein Journal of Nanotechnology 10 (January 24, 2019): 274–80. http://dx.doi.org/10.3762/bjnano.10.26.

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Анотація:
We report on the growth of ZnO nanocrystals having a hexagonal, prismatic shape, sized 700 nm × 600 nm, on bare indium tin oxide (ITO) substrates. The growth is induced by a low ion flux and involves a low-temperature electrodeposition technique. Further, vertically aligned periodic nanocrystal (NC) growth is engineered at predefined positions on polymer-coated ITO substrates patterned with ordered pores. The vertical alignment of ZnO NCs along the c-axis is achieved via ion-by-ion nucleation-controlled growth for patterned pores of size ≈600 nm; however, many-coupled branched NCs with hexagonal shape are formed when a patterned pore size of ≈200 nm is used. X-ray diffraction data is in agreement with the observed morphology. A mechanism is proposed to interpret the observed site-specific oriented/branched growth that is correlated to the pore size. As ordered NC arrays have the potential to generate new collective properties different from single NCs, our first demonstration of a cost effective and facile fabrication process opens up new possibilities for devices with versatile functionalities.
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Дисертації з теми "ZnO nanocrystal"

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Chieh-Yi, Kuo. "Fabrication and Optical Properties of ZnO Nanocrystal/GaN Quantum Well Based Hybrid Structures." Thesis, Linköpings universitet, Tunnfilmsfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-81675.

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Анотація:
Optical properties of hybrid structures based on zinc oxide nanocrystals (NCs) and Gallium Nitride quantum well (QW) has been studied. The ZnO NCs thin films on the top of GaN QW structures were fabricated using spin coating. The surface morphology was characterized by scanning electron microscopy (SEM). We have performed temperature dependence time-resolved photoluminescence (TRPL) measurements of the bare AlGaN/GaN QW structures and hybrids, containing ZnO NCs. It was found that at some temperatures the QW PL decay has shorter decay time in the presence of ZnO NCs thin film compared to the bare QW. The effect was stronger for the samples with thinner cap layers. The results are discussed in terms of three models such as exciton nonradiative energy transfer (NRET), tunneling effect, and piezoelectric field influence on the QW exciton energy.
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2

Ericsson, Leif KE. "Growth and Characterization of ZnO Nanocrystals." Doctoral thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-27156.

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The understanding of surfaces of materials is of crucial importance to all of us. Considering nanocrystals (NCs), that have a large surface to bulk ratio, the surfaces become even more important. Therefore, it is important to understand the fundamental surface properties in order to use NCs efficiently in applications. In the work reported in this thesis ZnO NCs were studied. At MAX-lab in Lund, synchrotron radiation based Spectroscopic Photoemission and Low Energy Electron Microscopy (SPELEEM) and X-ray Photoelectron Spectroscopy (XPS) were used. At Karlstad University characterization was done using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), Scanning Tunnelling Microscopy (STM), Auger Electron Spectroscopy (AES), and XPS. The fundamental properties of ZnO surfaces were studied using distributions of ZnO NCs on SiO2/Si surfaces. The conditions for distribution of ZnO NCs were determined to be beneficial when using ethanol as the solvent for ultrasonically treated dispersions. Annealing at 650 °C in UHV cleaned the surfaces of the ZnO NCs enough for sharp LEEM imaging and chemical characterization while no sign of de-composition was found. A flat energy band structure for the ZnO/SiO2/Si system was proposed after 650 °C. Increasing the annealing temperature to 700 °C causes a de-composition of the ZnO that induce a downward band bending on the surfaces of ZnO NCs. Flat ZnO NCs with predominantly polar surfaces were grown using a rapid microwave assisted process. Tuning the chemistry in the growth solution the growth was restricted to only plate-shaped crystals, i.e. a very uniform growth. The surfaces of the NCs were characterized using AFM, revealing a triangular reconstruction of the ZnO(0001) surface not seen without surface treatment at ambient conditions before. Following cycles of sputtering and annealing in UHV, we observe by STM a surface reconstruction interpreted as 2x2 with 1/4 missing Zn atoms.
Baksidestext The understanding of the surfaces of materials is of crucial importance to all of us. Considering nanocrystals (NCs), that have a large surface to bulk ratio, the surfaces become even more important. In the work in this thesis ZnO NCs were studied. The fundamental properties of ZnO surfaces were studied using distributions of ZnO NCs on SiO2/Si surfaces. Annealing at 650 °C in UHV cleaned the surfaces of the ZnO NCs enough for sharp LEEM imaging and chemical characterization while no sign of de-composition was found. A flat energy band structure for the ZnO/SiO2/Si system was proposed after 650 °C. Increasing the annealing temperature to 700 °C causes a de-composition of the ZnO that induce a downward band bending on the surfaces of ZnO NCs. Flat ZnO NCs with predominantly polar surfaces were grown using a microwave assisted process. Tuning the chemistry in the growth solution the growth was restricted to only plate-shaped crystals, i.e. a very uniform growth. The surfaces of the NCs were characterized using AFM, revealing a triangular reconstruction of the ZnO(0001) surface not seen without surface treatment at ambient conditions before. Following cycles of sputtering and annealing in UHV, we observe by STM a surface reconstruction interpreted as 2x2 with 1/4 missing Zn atoms.
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3

Dias, Eva. "The photophysics of CdSe/ZnS/CdSe core/barrier/shell nanocrystals: light harvesting, single nanocrystal blinking, and optical gain." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107729.

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This thesis investigates the photophysical properties of CdSe/ZnS/CdSe core/barrier/shell nanocrystals using a combination of steady state and time resolved spectroscopy. Interestingly, these materials exhibit photoluminescence (PL) from both the CdSe core and CdSe shell, which can be exploited for a variety of applications, such as white light emission and optical gain. Steady state measurements shed light on the coupling between the two CdSe phases. The CdSe shell is shown to have a significant influence upon the optical properties of the CdSe core. In fact, the CdSe shell acts as a light harvester, increasing the brightness of the CdSe core as compared to bare CdSe nanocrystals. Single nanocrystal spectra of CdSe/ZnS/CdSe revealed that both CdSe phases exhibited PL intermittency and spectral diffusion. No correlation was observed in the spectral diffusion of the two CdSe phases on the timescale of the measurement. However, the single nanocrystal PL linewidths suggest that spectral diffusion of the two CdSe phases differs on shorter timescales. Using ultrafast transient absorption spectroscopy, CdSe/ZnS/CdSe nanocrystals were shown to exhibit optical gain with enhancements over bare CdSe nanocrystals. The bandwidth of stimulated emission from CdSe/ZnS/CdSe nanocrystals was much broader than bare CdSe nanocrystals due to CdSe shell enabled states. CdSe/ZnS/CdSe nanocrystals were also found to have lower biexciton binding energies than CdSe nanocrystals, contributing to improved gain performance. In addition, higher energy bleaching features in the transient absorption spectra indicated that populations of excitons remain in higher energy states, enabling dual colour emission.
Cette thèse explore les propriétés photophysique du coeur/barrière/coquille des nanocrystaux de CdSe/ZnS/CdSe par une combinaison de spectroscopies à l'état d'équilibre et en temps résolu. Il est intéréssant de noter que ces matériaux présentent de la photoluminescence (PL) provenant du coeur CdSe et de la coquille CdSe qui pourrait être exploitée dans une variété d'applications comme l'émission de lumière blanche et gain optique. Des mesures à l'état d'équilibre ont illustré le couplage entre les deux phases de CdSe. On a démontré que la coquille de CdSe influence les propriétés optique du coeur de CdSe. En effect, la coquille de CdSe fonctionne comme collecteur de lumière, augmentant la luminosité du coeur de CdSe comparé aux nanocrystaux nus de CdSe. Les spectres de nanocrystaux simples de CdSe/ZnS/CdSe révèlent que les deux phases CdSe montrent de l'intermittence PL et de la diffusion spectrale. Aucune corrélation n'a été observée dans la diffusion spectrale des deux phases de CdSe à l'échelle de mesure. Par contre, les largeurs de raie de PL du simple nanocrystal suggère que la diffusion spectrale des deux phases de CdSe diffèrent à des échelles de temps plus courtes. Par spectroscopie ultrarapide d'absorption transitoire, on a démontré que les nanocrystaux de CdSe/ZnS/CdSe font preuve de gain optique amélioré sur les nanocrystaux de CdSe nus. La largeur de raie des émissions stimulées des nanocrystaux de CdSe/ZnS/CdSe était plus élargie que celle des nanocrystaux de CdSe à cause de la présence de la coquille de CdSe. On a aussi démontré que les nanocrystaux de CdSe/ZnS/CdSe ont des plus basses énergies de liaisons de biexciton que les nanocrystaux de CdSe, contribuant à une amélioration de performance de gain. De plus, des caractéristiques de blanchiment à haute énergie dans les spectres d'absorption transitoire indiquent que les populations d'excitons demeurent à des états d'énergie plus élevés, permettant une émission double en couleur.
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4

Wang, Jianpu. "Optoelectronic properties and memory effects of ZnO nanocrystals." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611743.

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5

Lee, Kwang Jik. "Study of stability of ZnO nanoparticles and growth mechanisms of colloidal ZnO nanorods." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4303.

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Анотація:
After hydrolyzing zinc acetate in methanol solution, spherical ZnO nanoparticles in the size range from about 2.5 to 5 nm were synthesized by maintaining a ZnO concentration of 0.02M. Compared to ZnO nanoparticles prepared via other methods, the particles prepared using our novel colloidal chemistry exhibit narrow size distribution and a high sensitivity to the surrounding environment. The structure and composition of the white powders precipitated from the colloidal solution can vary, depending on how the powder samples are prepared. Factors such as desorption and adsorption of methanol, binding of water and exposure to humid air have been studied to correlate to the structure and composition observed from the precipitated powder. Methanol desorption rate and excess KOH on the particle surface have played an important role in the structural changes. Furthermore, upon annealing, the white precipitate is recovered to wurtize ZnO. XRD and TEM are used to study the structural transformation of ZnO nanoparticles.
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6

Доброжан, Олександр Анатолійович, Александр Анатольевич Доброжан, Oleksandr Anatoliiovych Dobrozhan, Станіслав Ігорович Кахерський, Станислав Игорович Кахерский, Stanislav Ігорович Kakherskyi, Роман Миколайович Пшеничний та ін. "Cтруктурні та субструктурні характеристики нанокристалів і плівок ZnO для використання у сонячній енергетиці". Thesis, Дніпровський національний університет імені Олеся Гончара, 2020. https://essuir.sumdu.edu.ua/handle/123456789/80943.

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7

Zhou, Shengqiang. "Transition metal implanted ZnO: a correlation between structure and magnetism." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1209998012687-36583.

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Анотація:
Nowadays ferromagnetism is often found in potential diluted magnetic semiconductor systems. However, many authors question the origin of this ferromagnetism, i.e. if the observed ferromagnetism stems from ferromagnetic precipitates rather than from carriermediated magnetic coupling of ionic impurities, as required for a diluted magnetic semiconductor. In this thesis, this question will be answered for transition-metal implanted ZnO single crystals. Magnetic secondary phases, namely metallic Fe, Co and Ni nanocrystals, are formed inside ZnO. They are - although difficult to detect by common approaches of structural analysis - responsible for the observed ferromagnetism. Particularly Co and Ni nanocrystals are crystallographically oriented with respect to the ZnO matrix. Their structure phase transformation and corresponding evolution of magnetic properties upon annealing have been established. Finally, an approach, pre-annealing ZnO crystals at high temperature before implantation, has been demonstrated to sufficiently suppress the formation of metallic secondary phases.
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Urgessa, Zelalem Nigussa. "Growth and characterization of ZnO nanorods using chemical bath deposition." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1021124.

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Анотація:
Semiconductor devices are commonplace in every household. One application of semiconductors in particular, namely solid state lighting technology, is destined for a bright future. To this end, ZnO nanostructures have gained substantial interest in the research community, in part because of its requisite large direct band gap. Furthermore, the stability of the exciton (binding energy 60 meV) in this material, can lead to lasing action based on exciton recombination and possibly exciton interaction, even above room temperature. Therefore, it is very important to realize controllable growth of ZnO nanostructures and investigate their properties. The main motivation for this thesis is not only to successfully realize the controllable growth of ZnO nanorods, but also to investigate the structure, optical and electrical properties in detail by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy (steady state and time resolved) and X-ray diffraction (XRD). Furthermore, strong rectification in the ZnO/p-Si heterojunction is demonstrated. Nanorods have been successfully synthesized on silicon by a two-step process, involving the pre-coating of the substrate by a seed layer, followed by the chemical bath deposition of the nanorods. ZnO seed layers with particle sizes of about 5 nm are achieved by the thermal decomposition of zinc acetate dihydrate dissolved in ethanol. The effects of the seed layer density on the distribution, alignment and uniformity of subsequently grown nanorods were studied. The aspect ratio, orientation and distribution of nanorods are shown to be well controlled through adjusting the density of the ZnO nanoparticles pre-coated onto the substrates. It is shown that the seed layer is a prerequisite for the growth of well aligned ZnO nanorods on lattice mismatched Si substrate. The influence of various nanorod growth parameters on the morphology, optical and electrical properties of the nanorods were also systematically studied. These include the oxygen to zinc molar ratio, the pH of the growth solution, the concentration of the reactants, the growth temperature and growth time, different hydroxide precursors and the addition of surface passivating agents to the growth solution. By controlling these xii parameters different architectures of nanostructures, like spherical particles, well aligned nanorods, nanoflowers and thin films of different thicknesses are demonstrated. A possible growth mechanism for ZnO nanostructures in solution is proposed. XRD indicated that all the as-grown nanostructures produced above 45 C crystallize in the wurtzite structure and post growth annealing does not significantly enhance the crystalline quality of the material. In material grown at lower temperature, traces of zinc hydroxide were observed. The optical quality of the nanostructures was investigated using both steady-state PL and time-resolved (TR) PL from 4 K to room temperature. In the case of as-grown samples, both UV and defect related emissions have been observed for all nanostructures. The effect of post-growth annealing on the optical quality of the nanostructures was carefully examined. The effect of annealing in different atmospheres was also investigated. Regardless of the annealing environment annealing at a temperature as low as 300 C enhances the UV emission and suppresses defect related deep level emission. However, annealing above 500 C is required to out-diffuse hydrogen, the presence of which is deduced from the I4 line in the low temperature PL spectra of ZnO. TRPL was utilized to investigate lifetime decay profiles of nanorods upon different post growth treatments. The bound exciton lifetime strongly depends on the post-growth annealing temperature: the PL decay time is much faster for as grown rods, confirming the domination of surface assisted recombination. In general, the PL analysis showed that the PL of nanorods have the same characteristics as that of bulk ZnO, except for the stronger contribution from surface related bound excitons in the former case. Surface adsorbed impurities causing depletion and band bending in the near surface region is implied from both time resolved and steady state PL. Finally, although strong rectification in the ZnO/p-Si heterojunction is illustrated, no electroluminescence has been achieved. This is explained in terms of the band offset between ZnO and Si and interfacial states. Different schemes are proposed to improve the performance of ZnO/Si heterojunction light emitting devices.
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9

Tu, Wei-Lun Scharf Thomas W. "Processing, structure, and tribological property interrelationships in sputtered nanocrystalline ZnO coatings." [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/ark:/67531/metadc12207.

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10

Zhou, Shengqiang. "Transition metal implanted ZnO: a correlation between structure and magnetism." Doctoral thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A23718.

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Анотація:
Nowadays ferromagnetism is often found in potential diluted magnetic semiconductor systems. However, many authors question the origin of this ferromagnetism, i.e. if the observed ferromagnetism stems from ferromagnetic precipitates rather than from carriermediated magnetic coupling of ionic impurities, as required for a diluted magnetic semiconductor. In this thesis, this question will be answered for transition-metal implanted ZnO single crystals. Magnetic secondary phases, namely metallic Fe, Co and Ni nanocrystals, are formed inside ZnO. They are - although difficult to detect by common approaches of structural analysis - responsible for the observed ferromagnetism. Particularly Co and Ni nanocrystals are crystallographically oriented with respect to the ZnO matrix. Their structure phase transformation and corresponding evolution of magnetic properties upon annealing have been established. Finally, an approach, pre-annealing ZnO crystals at high temperature before implantation, has been demonstrated to sufficiently suppress the formation of metallic secondary phases.
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Книги з теми "ZnO nanocrystal"

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Rao, M. S. Ramachandra, and Tatsuo Okada, eds. ZnO Nanocrystals and Allied Materials. New Delhi: Springer India, 2014. http://dx.doi.org/10.1007/978-81-322-1160-0.

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Rao, M. S. Ramachandra, and Tatsuo Okada. ZnO Nanocrystals and Allied Materials. Springer London, Limited, 2013.

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Rao, M. S. Ramachandra, and Tatsuo Okada. ZnO Nanocrystals and Allied Materials. Springer (India) Private Limited, 2013.

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Okada, Tatsuo, and M. S. Ramachandra Rao. ZnO Nanocrystals and Allied Materials. Springer, 2016.

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Частини книг з теми "ZnO nanocrystal"

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Okazaki, K., T. Shimogaki, I. A. Palani, M. Higashihata, D. Nakamura, and T. Okada. "Lasing Characteristics of an Optically-Pumped Single ZnO Nanocrystal and Nanomachining for Controlling Oscillation Wavelength." In ZnO Nanocrystals and Allied Materials, 101–23. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_5.

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Senthil Kumar, E., Shubra Singh, and M. S. Ramachandra Rao. "Zinc Oxide: The Versatile Material with an Assortment of Physical Properties." In ZnO Nanocrystals and Allied Materials, 1–38. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_1.

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Venkataramesh, B., and Nilesh J. Vasa. "Synthesis of Polycrystalline Silicon Carbide (SiC) Thin Films Using Pulsed Laser Deposition." In ZnO Nanocrystals and Allied Materials, 217–32. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_10.

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Premkumar, T., Y. F. Lu, and K. Baskar. "Preparation and Characterization of ZnO Nanorods, Nanowalls, and Nanochains." In ZnO Nanocrystals and Allied Materials, 233–46. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_11.

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Thiyagarajan, P., M. Kottaisamy, and M. S. Ramachandra Rao. "Synthesis and Characterization of ZnO-Based Phosphors and Related Phosphor Composites in Bulk, Thin Film and Nano Form." In ZnO Nanocrystals and Allied Materials, 247–68. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_12.

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Kitture, Rohini, Sandip Dhobale, and S. N. Kale. "Zinc Oxide Nanomaterials as Amylase Inhibitors and for Water Pollution Control." In ZnO Nanocrystals and Allied Materials, 269–87. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_13.

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Suryanarayanan, R. "Zinc Oxide: From Optoelectronics to Biomaterial—A Short Review." In ZnO Nanocrystals and Allied Materials, 289–307. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_14.

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Kumar, J., S. Ramasubramanian, R. Thangavel, and M. Rajagopalan. "On the Optical and Magnetic Properties of Doped-ZnO." In ZnO Nanocrystals and Allied Materials, 309–29. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_15.

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Sakai, K., K. Ishikura, A. Fukuyama, I. A. Palani, M. S. Ramachandra Rao, T. Okada, and T. Ikari. "Low-Temperature Photoluminescence of Sb-doped ZnO Nanowires Synthesized on Sb-coated Si Substrate by Chemical Vapor Deposition Method." In ZnO Nanocrystals and Allied Materials, 331–39. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_16.

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Jayakumar, O. D., C. Persson, A. K. Tyagi, and C. Sudakar. "Experimental and Theoretical Investigations of Dopant, Defect, and Morphology Control on the Magnetic and Optical Properties of Transition Metal Doped ZnO Nanoparticles." In ZnO Nanocrystals and Allied Materials, 341–70. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_17.

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Тези доповідей конференцій з теми "ZnO nanocrystal"

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Panin, Gennady, Andrey Baranov, Olesya Kapitanova, Tae Won Kang, Jisoon Ihm, and Hyeonsik Cheong. "Optical Properties of ZnO∕MgO Nanocrystal Structures." In PHYSICS OF SEMICONDUCTORS: 30th International Conference on the Physics of Semiconductors. AIP, 2011. http://dx.doi.org/10.1063/1.3666510.

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Newton, M. C., P. A. Warburton, and S. Firth. "Ultraviolet photoresponse of ZnO tetrapod nanocrystal Schottky diodes." In 2006 Sixth IEEE Conference on Nanotechnology. IEEE, 2006. http://dx.doi.org/10.1109/nano.2006.247685.

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Wu, Jingda, and Lih Lin. "Flexible ZnO Nanocrystal Ultraviolet Photodetector on Bio-membrane." In CLEO: Science and Innovations. Washington, D.C.: OSA, 2014. http://dx.doi.org/10.1364/cleo_si.2014.sth4i.8.

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Zhang, Yaozhong, Daniel C. Ratchford, Rebecca J. Anthony, and Junghoon Yeom. "ZnO nanowire and silicon nanocrystal heterostructures for photocatalytic applications." In 2017 IEEE 17th International Conference on Nanotechnology (IEEE-NANO). IEEE, 2017. http://dx.doi.org/10.1109/nano.2017.8117484.

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Okazaki, Kota, Tetsuya Shimogaki, Koshi Fusazaki, Mitsuhiro Higashihata, Daisuke Nakamura, Naoto Koshizaki, and Tatsuo Okada. "Lasing characteristics of optically-pumped single ZnO micro/nanocrystal." In SPIE OPTO, edited by Ferechteh Hosseini Teherani, David C. Look, and David J. Rogers. SPIE, 2013. http://dx.doi.org/10.1117/12.2004424.

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Chubenko, E. B., M. I. Dolmatovich, and V. P. Bondarenko. "Electrochemical deposition of ZnO/Er thin films and nanocrystal arrays." In 2014 24th International Crimean Conference "Microwave & Telecommunication Technology" (CriMiCo). IEEE, 2014. http://dx.doi.org/10.1109/crmico.2014.6959607.

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Wang, Zhijun, Shouchun Li, Youming Lu, Dongxu Zhao, Jiayi Liu, Lianyuan Wang, Jinbao Zhang, Yanwei Gao, and Zeheng Wang. "Preparation, characterization, and optical properties of carbon doped ZnO nanocrystal." In SPIE Proceedings, edited by Wei Lu and Jeff Young. SPIE, 2006. http://dx.doi.org/10.1117/12.667707.

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Filali, Brahim El, Tetyana Torchynska, Georgiy Polupan, Erick Velázquez Lozada, José A. Andraca Adame, and Jorge L. Ramirez Garcia. "MORPHOLOGY, EMISSION AND CRYSTAL STRUCTURE OF ZnO NANOCRYSTAL FILMS CO-DOPED WITH Ga AND In ELEMENTS." In RAP Conference. Sievert Association, 2021. http://dx.doi.org/10.37392/rapproc.2021.04.

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Greenberg, Melisa R., Gennady A. Smolyakov, Timothy J. Boyle, and Marek Osiński. "Synthesis and characterization of ZnO and ZnO/ZnS colloidal nanocrystals." In Biomedical Optics (BiOS) 2007, edited by Marek Osinski, Thomas M. Jovin, and Kenji Yamamoto. SPIE, 2007. http://dx.doi.org/10.1117/12.717630.

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Gawai, U. P., H. A. Khawal, M. R. Bodke, and B. N. Dole. "Effect of silver doping on ZnO nanocrystals." In INTERNATIONAL CONFERENCE ON CONDENSED MATTER AND APPLIED PHYSICS (ICC 2015): Proceeding of International Conference on Condensed Matter and Applied Physics. Author(s), 2016. http://dx.doi.org/10.1063/1.4946658.

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Звіти організацій з теми "ZnO nanocrystal"

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White, C. W., J. D. Budai, and A. L. Meldrum. Ion beam synthesis of CdS, ZnS, and PbS compound semiconductor nanocrystals. Office of Scientific and Technical Information (OSTI), December 1997. http://dx.doi.org/10.2172/564245.

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Joshi, Pooran, Brett Compton, Jianlin Li, Gerald Jellison, Jr, Chad Duty, and Zhiyun Chen. Develop Roll-to-Roll Manufacturing Process of ZrO2 Nanocrystals/Acrylic Nanocomposites for High Refractive Index Applications. Office of Scientific and Technical Information (OSTI), April 2015. http://dx.doi.org/10.2172/1224167.

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