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Articles de revues sur le sujet "Heterostructure Nano-materials"
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Huma, Tabasum, Nadimullah Hakimi, Muhammad Younis, Tanzeel Huma, Zhenhua Ge et Jing Feng. « MgO Heterostructures : From Synthesis to Applications ». Nanomaterials 12, no 15 (3 août 2022) : 2668. http://dx.doi.org/10.3390/nano12152668.
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The energy storage capacity of batteries and supercapacitors has seen rising demand and problems as large-scale energy storage systems and electric gadgets have become more widely adopted. With the development of nano-scale materials, the electrodes of these devices have changed dramatically. Heterostructure materials have gained increased interest as next-generation materials due to their unique interfaces, resilient structures and synergistic effects, providing the capacity to improve energy/power outputs and battery longevity. This review focuses on the role of MgO in heterostructured magnetic and energy storage devices and their applications and synthetic strategies. The role of metal oxides in manufacturing heterostructures has received much attention, especially MgO. Heterostructures have stronger interactions between tightly packed interfaces and perform better than single structures. Due to their typical physical and chemical properties, MgO heterostructures have made a breakthrough in energy storage. In perpendicularly magnetized heterostructures, the MgO’s thickness significantly affects the magnetic properties, which is good news for the next generation of high-speed magnetic storage devices.
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Slepchenkov, Michael M., Dmitry A. Kolosov, Igor S. Nefedov et Olga E. Glukhova. « Band Gap Opening in Borophene/GaN and Borophene/ZnO Van der Waals Heterostructures Using Axial Deformation : First-Principles Study ». Materials 15, no 24 (13 décembre 2022) : 8921. http://dx.doi.org/10.3390/ma15248921.
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One of the topical problems of materials science is the production of van der Waals heterostructures with the desired properties. Borophene is considered to be among the promising 2D materials for the design of van der Waals heterostructures and their application in electronic nanodevices. In this paper, we considered new atomic configurations of van der Waals heterostructures for a potential application in nano- and optoelectronics: (1) a configuration based on buckled triangular borophene and gallium nitride (GaN) 2D monolayers; and (2) a configuration based on buckled triangular borophene and zinc oxide (ZnO) 2D monolayers. The influence of mechanical deformations on the electronic structure of borophene/GaN and borophene/ZnO van der Waals heterostructures are studied using the first-principles calculations based on density functional theory (DFT) within a double zeta plus polarization (DZP) basis set. Four types of deformation are considered: uniaxial (along the Y axis)/biaxial (along the X and Y axes) stretching and uniaxial (along the Y axis)/biaxial (along the X and Y axes) compression. The main objective of this study is to identify the most effective types of deformation from the standpoint of tuning the electronic properties of the material, namely the possibility of opening the energy gap in the band structure. For each case of deformation, the band structure and density of the electronic states (DOS) are calculated. It is found that the borophene/GaN heterostructure is more sensitive to axial compression while the borophene/ZnO heterostructure is more sensitive to axial stretching. The energy gap appears in the band structure of borophene/GaN heterostructure at uniaxial compression by 14% (gap size of 0.028 eV) and at biaxial compression by 4% (gap size of 0.018 eV). The energy gap appears in the band structure of a borophene/ZnO heterostructure at uniaxial stretching by 10% (gap size 0.063 eV) and at biaxial compression by 6% (0.012 eV). It is predicted that similar heterostructures with an emerging energy gap can be used for various nano- and optoelectronic applications, including Schottky barrier photodetectors.
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Yin, Yunzhen, Yanyan Bu et Xiangfu Wang. « Simulation of light transmission through core-shell heterostructure nano-materials ». Chemical Physics 535 (juillet 2020) : 110785. http://dx.doi.org/10.1016/j.chemphys.2020.110785.
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Fu, Nanxin, Jiazhen Zhang, Yuan He, Xuyang Lv, Shuguang Guo, Xingjun Wang, Bin Zhao, Gang Chen et Lin Wang. « High-Sensitivity 2D MoS2/1D MWCNT Hybrid Dimensional Heterostructure Photodetector ». Sensors 23, no 6 (14 mars 2023) : 3104. http://dx.doi.org/10.3390/s23063104.
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A photodetector based on a hybrid dimensional heterostructure of laterally aligned multiwall carbon nanotubes (MWCNTs) and multilayered MoS2 was prepared using the micro-nano fixed-point transfer technique. Thanks to the high mobility of carbon nanotubes and the efficient interband absorption of MoS2, broadband detection from visible to near-infrared (520–1060 nm) was achieved. The test results demonstrate that the MWCNT-MoS2 heterostructure-based photodetector device exhibits an exceptional responsivity, detectivity, and external quantum efficiency. Specifically, the device demonstrated a responsivity of 3.67 × 103 A/W (λ = 520 nm, Vds = 1 V) and 718 A/W (λ = 1060 nm, Vds = 1 V). Moreover, the detectivity (D*) of the device was found to be 1.2 × 1010 Jones (λ = 520 nm) and 1.5 × 109 Jones (λ = 1060 nm), respectively. The device also demonstrated external quantum efficiency (EQE) values of approximately 8.77 × 105% (λ = 520 nm) and 8.41 × 104% (λ = 1060 nm). This work achieves visible and infrared detection based on mixed-dimensional heterostructures and provides a new option for optoelectronic devices based on low-dimensional materials.
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Ren, Lingling, et Baojuan Dong. « Ferroelectric Polarization in an h-BN-Encapsulated 30°-Twisted Bilayer–Graphene Heterostructure ». Magnetochemistry 9, no 5 (26 avril 2023) : 116. http://dx.doi.org/10.3390/magnetochemistry9050116.
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Recently, the emergent two-dimensional (2D) ferroelectric materials have provided new possibilities for the miniaturization of ferroelectric systems and the integration of novel 2D nano-electronic devices. In addition to the intrinsic ferroelectrics exfoliated from bulk, 2D heterostructures hybridized from electrically non-polarized van der Waals (vdW) materials have also been proven to be a promising platform for the construction of ferroelectricity. Here, we report 30° twisted bilayer–graphene (TBLG) incommensurate moiré superlattice encapsulated by hexagonal boron nitride (h-BN), in which robust hysteretic resistance was detected at the top interface between h-BN and the TBLG from room temperature down to 40 mK. The hysteretic phenomenon can be understood by the extra carrier induced by the interfacial 2D ferroelectric polarization, which is estimated to be around 0.7 pC/m. Our work of interfacial ferroelectric heterostructure achieved by a TBLG/h-BN hybrid system expands the 2D ferroelectric families and opens more possibilities for future coupling the ferroelectricity with rich electronic and optical properties in vdW twistronic devices.
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Wang, Qianqian, Yujie Ma, Li Liu, Shuyue Yao, Wenjie Wu, Zhongyue Wang, Peng Lv et al. « Plasma Enabled Fe2O3/Fe3O4 Nano-aggregates Anchored on Nitrogen-doped Graphene as Anode for Sodium-Ion Batteries ». Nanomaterials 10, no 4 (18 avril 2020) : 782. http://dx.doi.org/10.3390/nano10040782.
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Low electrical conductivity severely limits the application of Fe2O3 in lithium- and sodium-ion batteries. In respect of this, we design and fabricate Fe2O3/Fe3O4 nano-aggregates anchored on nitrogen-doped graphene as an anode for sodium-ion batteries with the assistance of microwave plasma. The highly conductive Fe3O4 in the composite can function as a highway of electron transport, and the voids and phase boundaries in the Fe2O3/Fe3O4 heterostructure facilitate Na+ ion diffusion into the nano-aggregates. Furthermore, the Fe–O–C bonds between the nano-aggregates and graphene not only stabilize the structural integrity, but also enhance the charge transfer. Consequently, the Fe2O3/Fe3O4/NG anode exhibits specific capacity up to 362 mAh g−1 at 100 mA g−1, excellent rate capability, and stable long-term cycling performance. This multi-component-based heterostructure design can be used in anode materials for lithium- and sodium-ion batteries, and potential opens a new path for energy storage electrodes.
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Shukla, Ayushi, et Pooja Srivastava. « Van der Waals Heterostructures for device Applications ». SAMRIDDHI : A Journal of Physical Sciences, Engineering and Technology 13, no 01 (30 juin 2021) : 48–52. http://dx.doi.org/10.18090/samriddhi.v13i01.9.
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Advent of two-dimensional (2D) materials owing to their extraordinary properties can revolutionize the field of nano-electronics. Experimental advancements have now made it possible to stack different 2D layers on top of each other to form a single system. Due to van der Waals bonding between the layers, the properties of each layer are not perturbed much. It helps in generating new functionalities for nano-electronics applications. The present paper focuses on the application of van der Waals heterostructure.
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Sun, Ying-Hui, Cong-Yan Mu, Wen-Gui Jiang, Liang Zhou et Rong-Ming Wang. « Interface modulation and physical properties of heterostructure of metal nanoparticles and two-dimensional materials ». Acta Physica Sinica 71, no 6 (2022) : 066801. http://dx.doi.org/10.7498/aps.71.20211902.
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<sec>Two-dimensional (2D) material has atomic smooth surface, nano-scale thickness and ultra-high specific surface area, which is an important platform for studying the interface interaction between metal nanoparticles (NPs) and 2D materials, and also for observing the surface atomic migration, structural evolution and aggregation of metal NPs in real time and <i>in situ</i>. By rationally designing and constructing the interfaces of metal NPs and 2D materials, the characterization of the interface structure on an atomic scale is very important in revealing the structure-property relationship. It is expected that the investigation is helpful in understanding the mechanism of interaction between metal and 2D materials and optimizing the performance of the devices based on metal-2D material heterojunctions.</sec><sec>In this review, the recent progress of interface modulation and physical properties of the heterostructure of metal NPs and 2D materials are summarized. The nucleation, growth, structural evolution and characterization of metal NPs on the surface of 2D materials are reviewed. The effects of metal NPs on the crystal structure, electronic state and energy band of 2D materials are analyzed. The possible interfacial strain and interfacial reaction are also included. Because of the modulation of electrical and optical properties of 2D materials, the performance of metal NPs-2D material based field effect transistor devices and optoelectronic devices are improved. This review is helpful in clarifying the physical mechanism of microstructure affecting the properties of metal NPs-2D material heterostructures on an atomic scale, and also in developing the metal-2D material heterostructures and their applications in the fields of electronic devices, photoelectric devices, energy devices, etc.</sec>
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Rotkin, Slava V., et Tetyana Ignatova. « (Invited) Multiplexed Label-Free Biosensing Using 2D-Heterostructures : Materials Stability and Signal Uniformity ». ECS Meeting Abstracts MA2022-01, no 8 (7 juillet 2022) : 692. http://dx.doi.org/10.1149/ma2022-018692mtgabs.
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Two-dimensional materials (2DM) has been already applied for bio- and chemical sensing[1],[2]. Even individual 2D materials often outperform bulk analogues, showing strong response and being compatible with flexible technologies, thus opening horizons for wearable and Point-of-Care applications[3]. Most recently, emergent need to achieve better, more precise and sensitive drug detection in medicine and health care has been addressed by developing new types of biosensors[4]. Extending properties of individual 2DMs by constructing their van der Waals heterostructures, either lateral or vertical, offers new response and/or transduction mechanisms and further improvement of device performance. Such heterostructures have potential for label-free biosensing and could be designed and/or integrated together to generate several signals in response to a single analyte. Such a capability enables a multimodal detection, which exceeds single-mode biosensing through its higher throughput, as well as by better ability to differentiate the analyte from background signals in a complex media, and potentially allows multiplexing (responding by several channels to a group of substances in parallel). Despite significant efforts were invested into discovery of newer and better 2D materials with biosensing capabilities, there is only limited knowledge of factors that could limit its performance. Indeed, atomically thin 2D materials have an ultimate surface-to-volume ratio which helps sensing, but may result in surface non-uniformities at the nanometer scale such as: atomic impurities, adsorbates, single atom and lattice defects, wrinkles and ruptures – to name just a few. Such defects may modulate their sensing properties. Here, a new multidimensional optical imaging technique will be presented which is capable to detect lattice mismatch and work function difference in the heterostructure material. Those result in strain and charge transfer and vary optical response at the nanometer scale, hard to detect and study by normal characterization tools. We present a vertical heterostructure comprised of monolayer graphene and single layer flakes of MoS2. An optical label-free detection of doxorubicin, a common cancer drug, is reported via three independent optical detection channels (photoluminescence shift, Raman shift and Graphene Enhanced Raman Scattering). Non-uniform broadening of components of multimodal signal correlates with the statistical distribution of local optical properties of the 2DM heterostructure. It will be shown how mapping of distribution for doping and strain (taken with sub-diffractional resolution) allows one to understand the role of those for modulation of electronic properties of 2D material. Acknowledgement: partial support is acknowledged from NSF CHE-2032582, CHE-2032601, DMR-1539916 and DMR-2011839 grants. [1] Oh, S.-H.; et.al, Nature Communications 2021, 12, 3824. [2] Bolotsky, A.; et.al, ACS Nano 2019, 13, 9781. [3] Pang, Y.; et.al, Small 2020, 16, 1901124. [4] Moradi, R; Small (2021). doi: 10.1002/smll.202104847
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Jariwala, Deep. « (Invited) 2D Dimensional Quantum Materials for CMOS and Beyond CMOS Devices ». ECS Meeting Abstracts MA2022-01, no 29 (7 juillet 2022) : 1292. http://dx.doi.org/10.1149/ma2022-01291292mtgabs.
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The isolation of a growing number of two-dimensional (2D) materials has inspired worldwide efforts to integrate distinct 2D materials into van der Waals (vdW) heterostructures. While a tremendous amount of research activity has occurred in assembling disparate 2D materials into “all-2D” van der Waals heterostructures and making outstanding progress on fundamental studies, practical applications of 2D materials will require a broader integration strategy. I will present our ongoing and recent work on integration of 2D materials with 3D electronic materials to realize logic switches and memory devices with novel functionality that can potentially augment the performance and functionality of Silicon technology. First, I will present our recent work on gate-tunable diode1 and tunnel junction devices2 based on integration of 2D chalcogenides with Si and GaN. Following this I will present our recent work on non-volatile memories based on Ferroelectric Field Effect Transistors (FE-FETs) made using a heterostructure of MoS2/AlScN3 and I also will present our work on Ferroelectric Diode (ferrodiode) devices4 also based on thin AlScN. If time permits, I will also cover our ongoing efforts in scaling FE-FETs based on MoS2 and AlScN to < 100 nm channel lengths over large areas and also discuss in-memory computing using ferrodiode devices and also touch upon our efforts in photonics and light trapping using 2D semiconductors. I will end by giving a broad perspective on future opportunities of 2D semiconductors in micro and nanoelectronics. References: Miao, J.; Liu, X.; Jo, K.; He, K.; Saxena, R.; Song, B.; Zhang, H.; He, J.; Han, M.-G.; Hu, W.; Jariwala, D. Nano Letters 2020, 20, (4), 2907-2915. Miao, J.; Leblanc, C.; Liu, X.; Song, B.; Zhang, H.; Krylyuk, S.; Davydov, A. V.; Back, T.; Glavin, N. R.; Jariwala, D.,2D Metal Selenide-Silicon Steep Sub-Threshold Heterojunction Triodes with High On-Current Density arXiv:2111.06396 Liu, X.; Wang, D.; Zheng, J.; Musavigharavi, P.; Miao, J.; Stach, E. A.; Olsson III, R. H.; Jariwala, D. Nano Letters 2021, 21, 3753–3761. Liu, X.; Zheng, J.; Wang, D.; Musavigharavi, P.; Stach, E. A.; Olsson III, R.; Jariwala, D. Applied Physics Letters 2021, 118, 202901
Thèses sur le sujet "Heterostructure Nano-materials"
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Dou, Ziwei. « Investigation on high-mobility graphene hexagon boron nitride heterostructure nano-devices using low temperature scanning probe microscopy ». Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/283618.
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This thesis presents several experiments, generally aiming at visualising the ballistic and topological transport on the high-mobility graphene/boron nitride heterostructure using the scanning gate microscope. For the first experiment, we use the scanning gate microscopy to map out the trajectories of ballistic carriers in high-mobility graphene encapsulated by hexagonal boron nitride and in a weak perpendicular magnetic field. We employ a magnetic focusing transport configuration to image carriers that emerge ballistically from an injector, follow a cyclotron path due to the Lorentz force from an applied magnetic field, and land on an adjacent collector probe. The local potential generated by the scanning tip in the vicinity of the carriers deflects their trajectories, modifying the proportion of carriers focused into the collector. By measuring the voltage at the collector while scanning the tip, we are able to obtain images with arcs that are consistent with the expected cyclotron motion. We also demonstrate that the tip can be used to redirect misaligned carriers back to the collector. For the second experiment, we investigate the graphene van der Waals structures formed by aligning monolayer graphene with insulating layers of hexagonal boron nitride which exhibit a moiré superlattice that is expected to break sublattice symmetry. However, despite an energy gap of several tens of millielectronvolts opening in the Dirac spectrum, electrical resistivity remains lower than expected at low temperature and varies between devices. While subgap states are likely to play a role in this behaviour, their precise nature is still unclear in the community. We therefore perform a scanning gate microscopy study of graphene moiré superlattice devices with comparable activation energy but with different charge disorder levels. In the device with higher charge impurity ($\sim$ 10$^-$ cm$^{-2}$) and lower resistivity ($\sim$ 10 k$\Omega$) at the Dirac point we observe scanning gate response along the graphene edges. Combined with simulations, our measurements suggest that enhanced edge doping is responsible for this effect. In addition, a device with low charge impurity ($\sim$ 10$^{9}$ cm$^{-2}$) and higher resistivity ($\sim$ 100 k$\Omega$) shows subgap states in the bulk. Our measurements provide alternative model to the prevailing theory in the literature in which the topological bandstructures of the graphene moiré superlattices entail an edge currents shunting the insulating bulk. In the third experiment, we continue our study in the graphene moir$\acute e$ superlattices with the newly reported non-local Hall signals at the main Dirac point. It has been associated with the non-zero valley Berry curvature due to the gap opening and the nonlocal signal has been interpreted as the signature of the topological valley Hall effects. However, the nature of such signal is still disputed in the community, due to the vanishing density of states near the Dirac point and the possible topological edge transport in the system. Various artificial contribution without a topological origin of the measurement scheme has also been suggested. In connection to the second experiment, we use the scanning gate microscope to image the non-local Hall resistance as well as the local resistance in the current path. By analysing the features in the two sets of images, we find evidence for topological Hall current in the bulk despite a large artificial components which cannot be distinguished in global transport measurement. In the last experiment, we show the development of a radio-frequency scanning impedance microscopy compatible with the existing scanning gate microscopy and the dilution refrigerator. We detailed the design and the implementation of the radio-frequency reflectometry and the specialised tip holder for the integration of the tip and the transmission lines. We demonstrate the capability of imaging local impedance of the sample by detecting the mechanical oscillation of the tip, the device topography, and the Landau levels in the quantum Hall regime at liquid helium temperature and milli-Kelvin temperature.
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FIORITO, SERGIO. « Multi-materials nano-heterostructures for combined therapy and diagnosis ». Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/1001111.
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The present dissertation is resulting from the work performed during the Ph.D. research activity carried out at the Italian Institute of Technology (IIT) under the supervision of Dr. Teresa Pellegrino (Nanomaterials for biomedical research line) of the Italian Institute of Technology and Fabio Canepa of the University of Genova. The thesis has been conducted in the framework of the ERC-founded project ICARO (ERC starting grant n° 678109, Principal Investigator: Dr. Teresa Pellegrino), whose main purpose is the development of novel inorganic nanostructures for radiotherapy and chemotherapy of cancer. Thus, this thesis aims to progress the field of nanomedicine. In particular, the first goal of this work is to synthesize innovative water stable chalcogenide nanoparticles, with the purpose of achieving nano-sized platforms capable of incorporating radioactive 64Cu ions, which would make such systems suitable for the use in radiotherapy and for positron emission tomography. The second goal is to explore the coupling of such chalcogenide nanocrystals with magnetic nanoparticles, which are already part of the nanoparticles’ portfolio available in the research group where this thesis was carried out. These nanoparticles have shown great potential for magnetic hyperthermia treatment of cancer and, in combination with radiotherapy, could result in a synergic and more effective cancer treatment. Thus, this thesis provides new ground in the rational design of multifunctional nano-heterostructures for cancer diagnosis and therapy.
The first chapter of this thesis deals with the synthesis, water transfer and radiolabeling of ZnS nanoparticles. A non-hydrolitycal thermal decomposition synthesis route was exploited in order to obtain quasi-spherical nanoparticles. Such nanoparticles have hydrophobic ligands on their surface and thus are stable in organic solvents. In order to successfully transfer them to water phase, the ligands were exchanged through a procedure that employs a multi-dentate amphiphilic polymer (cysteamine-poly(isobutylene-alt-maleic anhydride)-polyethylene glycol, CYS-PIMA-PEG), which resulted in inorganic colloids with perfect stability in aqueous phase. On this system, cation exchange reactions with both radioactive and non-radioactive copper were carried out. The optimized protocol for the radiolabeling of ZnS nanocrystals with 64Cu permitted to obtain high values of radiochemical yield (93%), defined as the percentage of the total activity used that is incorporated in the crystals, without losing colloidal stability during radiolabeling reaction or subsequent concentration and purification process. The results obtained indicate ZnS nanoparticles as an efficient nano-platform for the use in radiotherapy and positron emission tomography, given the fast, reproducible and easily clinical-translatable radiolabeling procedure resulting in quantitative incorporation of 64Cu ions.
In the second chapter we report the research activity carried out to couple in a single nano-heterostructure, the ZnS nanoparticles or copper-deficient copper sulfide nanoparticles (previously reported to be exploitable as radioisotopes carriers) with highly performing magnetic nanoparticles (iron oxide nanocubes, IONCs) or nano-heterostructures (gold-iron oxide dimers, Au@FeOy). Although the direct growth of ZnS domains on IONCs, through colloidal two-pot seeded-growth synthesis procedures, was not possible, this thesis succeeds on merging the different nanoparticles in a single nano-platform by exploiting the use of gold NPs as “linkers” between magnetic iron oxide domains and copper deficient Cu2-xS domains, using Au@FeOy dimers as seeds for the growth of copper sulfide domains. Thus, this procedure resulted in the production of FeOy@Au@Cu2-xS2 trimers, with the additional possibility to tune the size of the Cu2-xS domain by changing precursors’ concentration. These trimers were thoroughly characterized through diverse structural and magnetic analysis techniques (transition electron microscopy, X-ray diffraction, SQUID magnetometry and UV-VIS-NIR spectroscopy). In particular, magnetic properties measurements, allowed to conclude that the magnetic properties of the FeOy@Au@Cu2-xS trimers are comparable to the ones of the Au@FeOy dimers (used as seeds for the subsequent reaction of growth of Cu2-xS domain). In addition, the trimers display two localized surface plasmon resonance absorption bands, one assigned to the gold domain and the other assignable to the copper deficient copper sulfide domain, respectively localized in the first and second NIR biological windows and, consequently, exploitable in photothermal therapy.
In the third chapter, the newly synthesized trimers were transferred to water phase and tested for the application as carriers for 64Cu and as heating probes in magnetic hyperthermia and photothermal therapy. Different strategies were explored in order to develop a reproducible and high-yield water transfer protocol. Among them, a two-step ligand exchange procedure employing methoxy-poly(ethylene glycol)-thiol and poly(catechol)-poly(ethylene glycol) as amphiphilic ligands resulted in aqueous phase stable trimers with high water transfer procedure yield (> 80 %). FeOy@Au@Cu2-xS trimers were also successfully transferred to water, although with lower yields if compared to previous procedure, using a polymer coating procedure and employing commercially available and cost-effective poly-(maleic anhydride-alt-1-octadecene). Lastly, the developed nano-platform showed great relevance in the field of nanomedicine. Indeed, when employed in magnetic hyperthermia, trimers resulted in high SAR values, preserving the excellent hyperthermia performances of the Au@FeOy used as seeds for their synthesis and thus in line with the best magnetic nano-heterostructures reported so far. Radiolabeling reactions were performed on trimers, resulting in a radiochemical yield of 97 %, higher than any value reported so far for 64Cu incorporation in water stable nanocrystals. Furthermore, the stability of the trimers during the radiolabeling and subsequent purification procedures was likewise ensured by the use of CYS-PIMA-PEG as stabilizing agent, permitting to recover quantitatively the nanocrystals and the associated radioactivity. The performances of FeOy@Au@Cu2-xS trimers when used in photothermal heating were also tested under the exposure to 808 nm laser irradiation. Although when using high power density (4.67 W/cm2), a temperature increase of 33°C in five minutes was registered, the performances obtained with lower laser’s power density were limited. However, the possibility to tune the absorption wavelengths by means of changing gold and copper sulfide domain’s properties, gives space to further improvements for these multifunctional nano-heterostructures. To the best of our knowledge, the here described FeOy@Au@Cu2-xS trimers are the first ever reported nano-heterostructures able to combine in one single nano-object the possibility to perform magnetic hyperthermia, photothermal therapy and radiotherapy/positron emission tomography, thus allowing the possible development of more efficient cancer treatments.
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Ip, Brian Kau 1962. « Design trade-off study for delta-doped Si/SiGe heterostructure MOSFET's : The potential nano-MOSFET's ». Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282544.
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A design trade-off study for n-channel δ-doped Si/SiGe heterojunction MOSFET's has been performed using a combination of numerical simulation and analysis. The design parameters unique to the δ-doped Si/SiGe heterostructure MOSFET's have been studied in terms of their effects on short-channel immunity, off-state leakage and on-state current. Our study shows that cap and channel layer must always be made as thin as possible to reduce the separation of the mobile charge centroid from the surface, in which case better short-channel immunity, better leakage and driving ability will result. On the other hand, the setback layer thickness, potential well depth and δ-doping dose are found to be trade-off parameters. Design windows that based on the trade-off parameters were constructed to obtained optimal designs for 0.2. μm channel length and 1.5 V supply voltage, and 0.1 μm channel length and 1 V supply voltage δ-doped Si/SiGe heterojunction MOSFET's. When compared to similarly configured conventional bulk MOSFET's, the 0.2 μm-1.5V design has approximately the same characteristics while the 0.1 μm-1V design has a 25% advantage in short-channel immunity. The δ-doped Si/SiGe heterojunction MOSFET is then redesigned by removing the cap layer, which results in a smaller effective oxide thickness but lower low-field mobility. The new structure is found to produce a 0.1μm-1V design that has improvement of 22% in on-state current, 54% in off-state leakage and 17% in short-channel immunity over the structure with the cap layer. We further are successful in producing a 70nm-1.2V design with excellent characteristics that cannot be reached by conventional MOSFET's. We conclude that the δ-doped Si/SiGe heterojunction MOSFET's without a cap layer have a high potential as the future high-performance transistors that can deliver high speed, high density and low power applications.
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Miller, Derek. « Advancing electronic structure characterization of semiconducting oxide nano-heterostructures for gas sensing ». The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492639729205609.
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Zhang, Nan. « Propriétés électroniques de MoS2 / MoSe2van der Waals heterostructures ». Thesis, Toulouse, INSA, 2020. http://www.theses.fr/2020ISAT0017.
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Le sujet de ma thèse concerne l’étude des propriétés optiques fon-damentales des dichalcogénures des métaux de transition (DCMT)des couches ultra-mince et plus précisément les hétérostuctures con-stituées de matériaux MX2(où M est du molybdène (Mo) et X dusoufre (S) ou du sélénium (Se)), liées entre elles par des interactionsde type Van der Waals. Le premier chapitre de la thèse a été con-sacré pour la description des propriétés fondamentales générales des(DCMT) exfolié et amincie jusqu’une monocouche. Egalement, leshétérostuctures à base des DCMT ont été largement décrites.Le chapitre 2 décrit les techniques expérimentales mises à dispo-sition pour servir mon projet de recherche soit en terme de mesuresou en terme de préparation des échantillons.Dans le chapitre 3, je présente l’effet de la photo-génération surles propriétés des exciton émis inter-couche. La photo-générationétant identifié à partir une augmentation de l’énergie de dissociationdes trions (via luminescence) accompagnée par un changement carac-téristique du rapport d’intensité de photoluminescence d’exciton etde trion dans le MoS2. Simultanément, j’ai observé une diminutionde l’intensité de PL de l’exciton généré inter-couche. Par contre lesignal PL composé des excitons et trions dans la couche de MoSe2aété amélioré montrant que le transfert de charges inter-couche peutêtre contrôlé en contrôlant le niveau de dopage. Cet effet observéest persistant sur une échelle de temps de plusieurs heures, tant quel’échantillon est maintenu sous vide. Ceci indique un mécanisme im-pliquant la désorption, induite par un laser, des molécules physisor-bées à la surface de l’hétérostructure. Je soutiens cette hypothèse endévoilant la sensibilité du taux de photo-génération sur la longueurd’onde d’excitation. Le processus de photo- génération se produitbeaucoup plus rapidement pour les photons ayant une énergie plusélevée.Dans le chapitre 4, je présente le résultat de l’impact du motifmoiré sur le spectre d’exciton inter-couche dans l’hétérostructureMoS2/ MoSe2. La formation du motif moiré est un phénomène car-actéristique des empilements de van der Waals où, en raison de lafaible interaction entre les couches chacune conservent ses propresparamètres de réseau. Par conséquent, en raison d’un petit anglede torsion ou d’une discordance de réseau entre les monocouches, unpotentiel variable dans l’espace périodique peut être induit. Ce po-tentiel peut avoir un impact non trivial sur les propriétés optiques desexcitons intra et inter-couche des hétérostructures de dichalcogénurede métaux de transition. Ici, je montre des preuves expérimentalesde l’impact du motif de moiré sur l’émission intra-couche dans unehétérostructure de MoSe2/ MoS2encapsulée avec du nitrure de borehexagonal (h-BN). Le potentiel périodique dans le plan se traduit par une clivage de spectre d’émission et ou d’absorption de l’excitonet du trion dans la couche de MoSe2. La différence d’énergie ob-servée entre les pics clivés est tout à fait conforme aux prévisionsthéoriques. De plus, ce chapitre contient une description détailléede la manière dont l’orientation relative des flocons dans une tellehétérostructure peut être révélée par la spectroscopie de générationdu deuxième harmonique.Le chapitre 5 contient les résultats des études préliminaires surl’impact de la qualité des échantillons et la possibilité de générerune polarisation de vallée via l’application d’un champ magnétique.Dans ces études, trois types de structures sont comparés, à savoirle MoSe2préparé par CVD et le MoSe2encapsulé par h-BN, ainsique l’hétérostructure MoSe2 / MoS2. De plus, j’ai trouvé que laformation d’un motif moiré a un impact négligeable sur le facteur gde Landé sur la transition excitonique intra-layerIn my thesis, I concluded results of my three years investigation of the optical properties of MoSe2/MoS2 transition metal dichalcogenides heterostructures. Thesis starts with the general overview of the properties of transition metal dichalcogenides monolayers and their heterostucers. This is followed by the detailed description experimental techniques which wear used to characterize photoresponse of heterostructures and their preparation. Next three paragraphs are devoted to the rustles of my investigations:In chapter 3 the impact of characteristic for transition metal dichalcogenides effect photodoping on the interlayer exciton emission properties is presented. The photodoping isidentified by the increasing (upon illumination) trion dissociation energy, accompanied by a characteristic change of the exciton/trion photoluminescence intensity ratioin MoSe2. At the same time, I observe decreasing photoluminescence intensity of the interlayer exciton. In the same time the combined PL intensity of the exciton and the trion in MoSe2 is enhanced, showing that the interlayer charge transfer can be controlled by the doping level. This observed effect is persistent on a timescale of several hours, as long as the sample is maintained under vacuum. This indicate a mechanism involving laser induced desorption of molecules physisorbed on the surface of the heterostructure. I support this hypothesis by revealed sensitivity of the photodoping rate on the excitation wavelength. The process of photodoping occurs much faster for higher energy photons.In chapter 4 I present result of the impact of moiré pattern on the intralayer exciton spectrum in MoS2/MoSe2 heterostructure. The moiré pattern formation is a phenomenon characteristic for van der Waals stacks where due to the weak interlayer interaction the ingredient layers preserve their own lattice parameters. Therefore due to small twist angle or of lattice mismatch between the monolayers periodic spatially varying potential is induced. This potential can have nontrivial impact on the optical properties of both intra- and interlayer excitons of transition metal dichalcogenide heterostructures. Here, I show experimental evidences of the moiré pattern impact on intralayer emission in a MoSe2/MoS2 heterobilayer encapsulated in hexagonal boron nitride. The periodic in-plane potential results in a splitting of the MoSe2 exciton and trion in emission and (for the exciton) absorption spectra. The observed energy difference between the split peaks is fully consistent with theoretical predictions. Moreover this chapter contain detailed description how the relative orientation of the flakes in such heterostructure can be revealed by second harmonic generation spectroscopy.Chapter 5 contains result of the initial studies about the impact of sample quality and possibility to generate valley polarization by the magnetic field. In this studies three type of structures are compared namely CVD grown and h-BN encapsulated MoSe2, together with MoSe2/MoS2 heterostructure. In addition I found that the formation of moire pattern has negligible impact on the Lande g-factor on intralayer excitonic transition
Livres sur le sujet "Heterostructure Nano-materials"
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Yang, Shihe. Physics and Chemistry of Nano-Structured Materials. Taylor & Francis Group, 2003.
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Yang, Shihe. Physics and Chemistry of Nano-Structured Materials. Taylor & Francis Group, 2003.
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Yang, Shihe. Physics and Chemistry of Nano-structured Materials. CRC, 1999.
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Yang, Shihe. Physics and Chemistry of Nano-Structured Materials. Taylor & Francis Group, 2019.
Trouver le texte intégralChapitres de livres sur le sujet "Heterostructure Nano-materials"
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Kumano, Hidekazu, Ikuo Suemune, Katsumi Kishino, Shizuo Fujita, Adarsh Sandhu, Nobuo Suzuki et Kazuhiro Ohkawa. « Novel Nano-Heterostructure Materials and Related Devices ». Dans Wide Bandgap Semiconductors, 281–327. Berlin, Heidelberg : Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-47235-3_5.
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Hongpinyo, V., Y. H. Ding, J. Anderson, Hery S. Djie, Boon S. Ooi, R. R. Du, A. Ganjoo et H. Jain. « Sputtered SiO2 Induced Atomic Interdiffusion in Semiconductor Nano Heterostructures ». Dans Semiconductor Photonics : Nano-Structured Materials and Devices, 33–35. Stafa : Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-471-5.33.
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Pintilie, I., L. Pintilie, L. D. Filip, L. C. Nistor et C. Ghica. « Oxide Thin Films and Nano-heterostructures for Microelectronics (MOS Structures, Ferroelectric Materials and Multiferroic Heterostructures) ». Dans Size Effects in Nanostructures, 77–108. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44479-5_4.
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Netzer, Falko P., et Claudine Noguera. « Synopsis and outlook ». Dans Oxide Thin Films and Nanostructures, 263–68. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198834618.003.0009.
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The synopsis part of this last chapter gives a brief summary of the book content. The outlook attempts to identify future areas of scientific activity, in which according to the authors´ visions nano-oxide materials may promote new developments. Among them are the controlled synthesis of oxide nanosheets and the experimental realization of oxide nanoribbons. The preparation of well-defined oxide heterostructures may reveal novel emergent states and new topological phases of matter. Mixed nano-oxides will be of interest for band structure engineering and to adjust band edges for photochemical reactivity. Programmable defect chemistry may open up new selective pathways for catalytic reactions. In parallel with experimental progress, advanced theoretical and simulation methods will take advantage of the ever-increasing computer power to tackle highly correlated materials and allow highthroughput computing. The interaction of nano-oxides with biological systems has great potential for opening up new avenues in the biotechnological area.
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Miller, Derek R., et Sheikh A. Akbar. « Nano-Heterostructure Metal Oxide Gas Sensors : Opportunities and Challenges ». Dans Reference Module in Materials Science and Materials Engineering. Elsevier, 2020. http://dx.doi.org/10.1016/b978-0-12-803581-8.10301-7.
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Miller, Derek R., et Sheikh A. Akbar. « Nano-Heterostructure Metal Oxide Gas Sensors : Opportunities and Challenges ». Dans Encyclopedia of Smart Materials, 297–301. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-12-815732-9.10301-8.
Texte intégralActes de conférences sur le sujet "Heterostructure Nano-materials"
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Xu, Zaiquan, Caiyun Chen, Steve Q. Y. Wu, Bing Wang, Jinghua Teng, Chao Zhang et Qiaoliang Bao. « Graphene-polymer multilayer heterostructure for terahertz metamaterials ». Dans SPIE Micro+Nano Materials, Devices, and Applications, sous la direction de James Friend et H. Hoe Tan. SPIE, 2013. http://dx.doi.org/10.1117/12.2049533.
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Mukhopadhyay, Swarnav, Payel Halder et Arpan Deyasi. « Dependence of Threshold Voltage Shift on Material Composition for Si-Sir-Ge» Heterostructure p-MOSFET ». Dans 2019 3rd International Conference on Electronics, Materials Engineering & Nano-Technology (IEMENTech). IEEE, 2019. http://dx.doi.org/10.1109/iementech48150.2019.8981047.
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Lupan, Oleg, Nicolae Magariu, Helge Kruger, Alexandr Sereacov, Nicolai Ababii, Serghei Railean, Lukas Zimoch, Rainer Adelung et Sandra Hansen. « Nano-Heterostructured Materials - Based Sensors for Safety and Biomedical Applications ». Dans 2022 IEEE 12th International Conference Nanomaterials : Applications & Properties (NAP). IEEE, 2022. http://dx.doi.org/10.1109/nap55339.2022.9934724.
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Nirmal, H. K., Nisha Yadav, Pyare Lal et P. A. Alvi. « Optical gain in type–II InGaAs/GaAsSb quantum well nano-heterostructure ». Dans ADVANCED MATERIALS AND RADIATION PHYSICS (AMRP-2015) : 4th National Conference on Advanced Materials and Radiation Physics. AIP Publishing LLC, 2015. http://dx.doi.org/10.1063/1.4929254.
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Vitiello, Miriam S., et Leonardo Viti. « Efficient Room-temperature Terahertz Nano-detectors based on Novel 2D Materials and heterostructures ». Dans CLEO : Science and Innovations. Washington, D.C. : OSA, 2016. http://dx.doi.org/10.1364/cleo_si.2016.sth3i.5.
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Khan, M. Imran, Garima Bhardwaj, Sandhya Kattayat, Sandeep Sharma et P. A. Alvi. « Impact of temperature on optical properties of InGaAs/GaAsSb/InAlAs nano-scale heterostructure ». Dans NATIONAL CONFERENCE ON PHYSICS AND CHEMISTRY OF MATERIALS : NCPCM2020. AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0061072.
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Shruthi, Julakanti, Nagabandi Jayababu et M. V. Ramana Reddy. « Room temperature ethanol gas sensing performance of CeO2− In2O3 heterostructured nanocomposites ». Dans THE 3RD INTERNATIONAL CONFERENCE ON OPTOELECTRONIC AND NANO MATERIALS FOR ADVANCED TECHNOLOGY (icONMAT 2019). Author(s), 2019. http://dx.doi.org/10.1063/1.5093838.
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Jayababu, Nagabandi, Madhukar Poloju et M. V. Ramana Reddy. « Enhanced room temperature ammonia gas sensing performance of ZnO-Cr2O3 heterostructured nanocomposites ». Dans THE 3RD INTERNATIONAL CONFERENCE ON OPTOELECTRONIC AND NANO MATERIALS FOR ADVANCED TECHNOLOGY (icONMAT 2019). Author(s), 2019. http://dx.doi.org/10.1063/1.5093843.
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Eshghinejad, Ahmadreza, Wen-I. Liang, Qian Nataly Chen, Feiyue Ma, Ying-Hao Chu et Jiangyu Li. « Probing Multiferroic Heterostructures of BiFeO3-LiMn2O4 Using Magnetic, Piezoelectric and Piezomagnetic Force Microscopies ». Dans ASME 2014 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/smasis2014-7513.
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In this study magnetic force microscopy (MFM), piezoresponse force microscopy (PFM), and the newly developed piezomagnetic force microscopy (PmFM) techniques are used to probe the ferroelectric and ferromagnetic properties of BiFeO3-LiMn2O4 (BFO-LMO) heterostructures at nano-scale. The PmFM technique is also used to probe the ferromagnetic properties of CoFe2O4 (CFO) as a case study. The PFM and PmFM mappings of the BFO-LMO heterostructures clearly distinguish the BFO matrix and LMO nanopillars while the MFM mapping is ambiguous. The relatively high piezomagnetic response of BFO matrix is believed to be due to the Mn doping while the piezoelectric-like response of LMO nanopillars is due to the ionic activities and the vertical geometry of its heterostructure. Lastly, limitations of the PmFM technique are discussed.