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Hybrid dual-channel phototransistor based on 1D t-Se and 2D ReS2 mixed-dimensional heterostructures
摘要： The combination of mixed-dimensional semiconducting materials can provide additional freedom to construct integrated nanoscale electronic and optoelectronic devices with diverse functionalities. In this work, we report a high-performance dual-channel phototransistor based on one-dimensional (1D)/two-dimensional (2D) trigonal selenium (t-Se)/ReS2 heterostructures grown by chemical vapor deposition. The injection and separation efficiency of photogenerated electron–hole pairs can be greatly improved due to the high-quality interfacial contact between t-Se nanobelts and ReS2 films. Compared with bare ReS2 film devices, the dual-channel phototransistor based on t-Se/ReS2 heterostructure exhibits considerable enhancement with the responsivity (R) and detectivity (D*) up to 98 A·W–1 and 6 × 1010 Jones at 400 nm illumination with an intensity of 1.7 mW·cm?2, respectively. Besides, the response time can also be reduced by three times of magnitude to less than 50 ms due to the type-II band alignment at the interface. This study opens up a promising avenue for high-performance photodetectors by constructing mixed-dimensional heterostructures.
关键词： phototransistor,van der Waals heterostructures,ReS2,trigonal selenium (t-Se) nanobelt
更新于2025-09-23 15:23:52
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The production of graphene–boron nitride nanosheet heterostructures via liquid phase exfoliation assisted by a milling process
摘要： Graphene–boron nitride (BN) nanosheet heterostructures have become one of the highly interesting matters in recent times owing to their advantages. In this study, the liquid phase exfoliation method was preferred for production of graphene–BN nanosheet heterostructures. However, a pre-milling process was applied to starting materials, instead of the classical liquid phase exfoliation method previously used in the literature. Hexagonal graphite (h-G) and h-BN mixtures were milled for 50 h and the milled powders were subjected to the liquid phase exfoliation process. As a result of the examinations, it was observed that graphene–BN nanosheet heterostructures were successfully synthesized. The widths of the synthesized nanosheets were 300–500 nm and nanosheets were multi-layers. It was seen that a large part of the powder mixture were occurred at high amorphization during the ball milling process. According to X-ray diffraction (XRD) peaks, the amorphization ratio was almost 90%. But, almost all of amorphous structures were removed during acid mixing and the thermal process. But, amorphous structures still existed in samples. In addition, the ball milling process damaged the sheets and defects formed. Despite all these disadvantages, the milling process carried out in this study provided formation of thinner and larger sheets compared with previous similar studies.
关键词： ball milling,BN nanosheets,exfoliation,heterostructures,Graphene
更新于2025-09-23 15:23:52
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Interface properties of nonpolar LiAlO2/SrTiO3 heterostructures
摘要： Advances in creating metal oxide heterostructures have received a great deal of attention because novel properties like two-dimensional electron gas (2DEG), which was first found in LaAlO3/SrTiO3 interface, while does not exist in the bulk materials. To extend the study on 2DEG, we investigate the electronic property of interesting nonpolar/nonpolar LiAlO2/SrTiO3 heterostructure (also perovskite/nonperovskite oxide heterostructure), with and without oxygen vacancies by first-principles calculations. Two types of interfaces, SrO/LiAlO2 and TiO2/LiAlO2 interfaces, were modeled with the stable stacking configurations. Oxygen vacancies at LiAlO2/SrTiO3 interface induce the carriers in this system. there is no 2DEG behavior detected. Our results show that three-dimensional transport behavior occurs in the perovskite/non-perovskite oxide interface.
关键词： Metal oxide heterostructures,First-principles calculations,Oxygen vacancies,LiAlO2,SrTiO3
更新于2025-09-23 15:23:52
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Two-dimensional amorphous heterostructures of Ag/a-WO3- for high-efficiency photocatalytic performance
摘要： Synergistic photocatalysis is an important concept for designing the high-efficiency catalysis for fundamental research and technical applications. In this study a well-defined synergistic photocatalysis system is realized by the 2D amorphous heterostructures (2DAHs) Ag/a-WO3-x, which are constructed by Ag nanoparticles on 2D amorphous tungsten oxide (a-WO3-x) fabricated via supercritical CO2 method. We demonstrate theoretically that the oxygen evolution reactions (OER), characterized by photocurrent response, have been dramatically improved in Ag/a-WO3-x than those of both single a-WO3-x and Ag/WO3 systems. Such an enhanced photoelectrochemical performance attributes to the superposition effect of amorphous effect catalysis and local surface plasmon resonances (LSPR) catalysis. More interestingly, the ab initio density-functional theory calculations reveal that the amorphous effect catalysis ascribes to the unique d-d tail states coupling of both Ag and W atoms in the 2DAHs. Overall, our findings not only propose the prototype of synergistic photocatalysis, but also provide a new methodology to the design of novel catalyst.
关键词： 2D amorphous tungsten oxide,amorphous effect catalysis,synergistic photocatalysis,d-d tail states coupling,2D amorphous heterostructures Ag/a-WO3-x
更新于2025-09-23 15:23:52
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Lateral interfaces of transition metal dichalcogenides: A stable tunable one-dimensional physics platform
摘要： We study in-plane lateral heterostructures of commensurate transition-metal dichalcogenides, such as MoS2-WS2 and MoSe2-WSe2, and find interfacial and edge states that are highly localized to these regions of the heterostructure. These are one-dimensional (1D) in nature, lying within the band gap of the bulk structure and exhibiting complex orbital and spin structure. We describe such heteroribbons with a three-orbital tight-binding model that uses first principles and experimental parameters as input, allowing us to model realistic systems. Analytical modeling for the 1D interfacial bands results in long-range hoppings due to the hybridization along the interface, with strong spin-orbit couplings. We further explore the Ruderman-Kittel-Kasuya-Yosida indirect interaction between magnetic impurities located at the interface. The unusual features of the interface states result in effective long-range exchange noncollinear interactions between impurities. These results suggest that transition-metal dichalcogenide interfaces could serve as stable, tunable 1D platform with unique properties for possible use in exploring Majorana fermions, plasma excitations, and spintronics applications.
关键词： spin-orbit coupling,interface states,transition metal dichalcogenides,RKKY interaction,tight-binding model,lateral heterostructures
更新于2025-09-23 15:23:52
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Giant-Shell CdSe/CdS Nanocrystals: Exciton Coupling to Shell Phonons Investigated by Resonant Raman Spectroscopy
摘要： The interaction between excitons and phonons in semiconductor nanocrystals plays a crucial role in the exciton energy spectrum and dynamics, and thus in their optical properties. We investigate the exciton-phonon coupling in giant-shell CdSe/CdS core-shell nanocrystals via resonant Raman spectroscopy. The Huang-Rhys parameter is evaluated by the intensity ratio of the longitudinal-optical (LO) phonon of CdS with its first multiscattering (2LO) replica. We used four different excitation wavelengths in the range from the onset of the CdS shell absorption to well above the CdS shell band edge to get insight into resonance effects of the CdS LO phonon with high energy excitonic transitions. The isotropic spherical giant-shell nanocrystals show consistently stronger exciton-phonon coupling as compared to the anisotropic rod-shaped dot-in-rod (DiR) architecture, and the 2LO/LO intensity ratio decreases for excitation wavelengths approaching the CdS band edge. The strong exciton-phonon coupling in the spherical giant-shell nanocrystals can be related to the delocalization of the electronic wave functions. Furthermore, we observe the radial breathing modes of the GS nanocrystals and their overtones by ultra-low frequency Raman spectroscopy with nonresonant excitation, using laser energies well below the band gap of the heteronanocrystals, and highlight the differences between higher order optical and acoustic phonon modes.
关键词： Giant-shell nanocrystals,acoustic phonons,Dot-in-rods,Raman spectroscopy,Core-shell heterostructures,exciton-phonon coupling
更新于2025-09-23 15:23:52
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Dispersion relations of elastic waves in three-dimensional cubical piezoelectric phononic crystal with initial stresses and mechanically and dielectrically imperfect interfaces
摘要： The shape of individual building blocks is an important parameter in bottom-up self-assembly of nano-structured materials. A simple shape change from sphere to spheroid can significantly affect the assembly process due to the modification to the orientational degrees of freedom. When a layer of spheres is placed upon a layer of spheroids, the strain at the interface can be minimized by the spheroid taking a special orientation. C70 fullerenes represent the smallest spheroids, and their interaction with a sphere-like C60 is investigated. We find that the orientation of the C70 within a close-packed C70 layer can be steered by contacting a layer of C60. This orientational steering phenomenon is potentially useful for epitaxial growth of multilayer van der Waals molecular heterostructures.
关键词： interface,self-assembly,epitaxy,scanning tunnelling microscopy,graphene,van der Waals heterostructures,fullerene
更新于2025-09-23 15:23:52
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Enhanced mobility in LaAlO3/SrTiO3 heterostructures with layer-modulated patterning
摘要： Overcoming the unintentional doping of defect-related carriers induced from low oxygen partial pressure is a major challenge to realize multifunctional oxide electronics. In this work, we demonstrate that the two-step deposition in conjunction with layer modulated patterning process can enhance several properties of LaAlO3/SrTiO3 (LAO/STO) heterostructures grown under a low oxygen partial pressure of 5 × 10?8 Torr. Specifically, our patterned samples exhibit extraordinary electronic properties including positive colossal magnetoresistance of ～3500% under 10 T, and enhanced carrier mobility ~5000 cm2/Vs at 2 K without using buffer layer or using additional elements. These unique phenomena are resulted from inhibition of the multiband conducting behaviour, which likely originates from oxygen vacancy related defects in the STO layers, through the two-step fabrication method. Consequently, by controlling defect behaviour through the two-step deposition jointly with modulated patterning process, several properties for oxide-based electronics can be induced in a single platform even under a low oxygen condition.
关键词： Oxide electronics,Heterostructures,Electronic properties
更新于2025-09-23 15:23:52
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heterostructures: Examination of spin relaxation mechanism
摘要： The thickness, temperature, and composition studies of spin diffusion length (SDL) and spin Hall angle (SHA) are performed by measuring the spin Hall magnetoresistance in Pd1?xPtx/Y3Fe5O12 (=YIG) heterostructures. The SDL is found to be invariant to changes in the electron momentum relaxation time by varying the temperature, the normal metal (NM) thickness, or the alloy composition, while the SHA exhibits a nonmonotonic dependence on temperature. These findings suggest the appearance of D’yakonov-Perel’ spin relaxation mechanism and phonon skew scattering in our heterostructures that is associated with strong interfacial Rashba spin-orbit coupling (IRSOC). At last, we employ the ab initio calculations to quantify the IRSOC at the inversion-symmetry-broken NM/YIG interface.
关键词： spin diffusion length,spin relaxation mechanism,spin Hall angle,interfacial Rashba spin-orbit coupling,PdPt/YIG heterostructures
更新于2025-09-23 15:23:52
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Organic/inorganic nitride heterostructure for efficient photocatalytic oxygen evolution
摘要： Given the four-electron water oxidation reaction as the rate-limiting step for water splitting, highly efficient photocatalysts for oxygen evolution have been receiving increasing research attentions. In this study, an organic/inorganic g-C3N4/CoN nitride heterostructure was developed by a facile precipitation-nitridation two-step process. With the CoN loading amounts optimized, the obtained g-C3N4/CoN composite achieves more than 4-fold increase in photocatalytic activity for oxygen evolution, as compared to the pristine g-C3N4, with a highest oxygen evolution rate reaching 607.2 μmol h?1 g?1 under visible light (λ > 420 nm). It was demonstrated that the formed g-C3N4/CoN heterostructure could promote the interfacial charge carrier separation and the loaded CoN acting as an effective cocatalyst could accelerate the water oxidation reaction kinetics, which synergistically contributes to the great enhancement in photocatalytic activity for oxygen evolution. Interestingly, by physically mixing g-C3N4/CoN and g-C3N4/Ni, acting as oxygen and hydrogen production photocatalysts, respectively, the obtained composite could stably produce oxygen and hydrogen in the stoichiometric ratio from pure water under visible light (λ > 420 nm). Although the photocatalytic overall water splitting activity is still very low, this study demonstrates a facile and promising approach to develop visible-light active photocatalysts for simultaneous hydrogen and oxygen production from water, from the perspective of surface modification and bifunctional cocatalyst loading.
关键词： Oxygen evolution,g-C3N4,Photocatalytic water splitting,Heterostructures
更新于2025-09-23 15:23:52