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Growth of Ultrathin Ternary Teallite (PbSnS2) Flakes for Highly Anisotropic Optoelectronics
摘要： Two-dimensional (2D) ternary materials have gained significant attention because of their additional degree of freedom stemming from the variable stoichiometry. However, the research on 2D ternary materials is still in the early stage because of the difficulty of synthesizing them. Here, ultrathin PbSnS2 flakes are synthesized via chemical vapor deposition (CVD) assisted by salt and a molecular sieve with thickness down to ~2.4 nm. Adding salt and a molecular sieve results in lowering of the melting point of metal precursors and uniformly distributed source vapors in the reaction system, respectively. Impressively, 2D PbSnS2 flake shows giant anisotropic mobility (marmchair/mzigzag = 1.78) and responsivity (Rzigzag/Rarmchair = 1.25). The employment of salt and a molecular sieve in the CVD process for successful synthesis of ultrathin PbSnS2 flakes may provide a new platform for the design of other 2D ternary materials.
关键词： ternary materials,anisotropic optoelectronics,PbSnS2,chemical vapor deposition,2D materials
更新于2025-09-16 10:30:52
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Self-Powered SnS1-xSex Alloy/Silicon Heterojunction Photodetectors with High Sensitivity in a Wide Spectral Range
摘要： Alloy engineering and heterostructures designing are two efficient methods to improve the photosensitivity of 2D material-based photodetectors. Herein, we report the first-principle calculation about the band structure of SnS1-xSex (0 ≤ x ≤ 1) and synthesize these alloy nanosheets. Systematic measurements indicate that SnS0.25Se0.75 exhibits the highest hole mobility (0.77 cm2·V-1·s-1) and a moderate photoresponsivity (4.44 × 102 A·W-1) with fast response speed (32.1/57.5 ms) under 635 nm irradiation. Furthermore, to reduce the dark current and strengthen the light absorption, a self-driven SnS0.25Se0.75/n-Si device has been fabricated. The device achieved a preeminent photo-responsivity of 377 mA·W-1, a detectivity of ~1011 Jones and Ilight/Idark ratio of ~4.5×102. In addition, the corresponding rising/decay times are as short as 4.7/3.9 ms. Moreover, a broadband sensitivity from 635 nm to 1200 nm is obtained and the related photoswitching curves are stable and reproducibility. Noticeably, the above parameters are comparable or superior to the most of reported group IVA layered materials-based self-driven photodetectors. Last, the synergistic effects between the SnS0.25Se0.75 nanosheets and the n-Si have been discussed by the band alignment. These brilliant results will pave a new pathway for the development of next generation 2D alloy-based photoelectronic devices.
关键词： alloy engineering,photodetectors,Tin chalcogenides,physical vapor deposition,van der Waals heterostructure
更新于2025-09-16 10:30:52
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TiO2 Coated ZnO Nanorods by Mist Chemical Vapor Deposition for Application as Photoanodes for Dye-Sensitized Solar Cells
摘要： In this study, a mist chemical vapor deposition method was applied to create a coating of titanium dioxide particles in order to fabricate ZnO/TiO2 core–shell nanostructures. The thin layers of titanium dioxide on the zinc oxide nanorods were uniform and con?rmed as pure anatase phase. The morphological, structural, optical and photoluminescence properties of the ZnO/TiO2 core–shell structures were in?uenced by coating time. For instance, the crystallinity of the titanium dioxide increased in accordance with an increase in the duration of the coating time. Additionally, the thickness of the titanium dioxide layer gradually increased with the coating time, resulting in an increased surface area. The transmittance of the arrayed ZnO/TiO2 core–shell structures was 65% after 15 min of coating. The obtained ZnO/TiO2 core–shell nanostructures demonstrated high potentiality to serve as photoanodes for application in dye-sensitized solar cells.
关键词： chemical bath deposition,titanium dioxide,core–shell nanorods,mist chemical vapor deposition,zinc oxide
更新于2025-09-12 10:27:22
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Controlled Growth and Thickness‐Dependent Conduction‐Type Transition of 2D Ferrimagnetic Cr <sub/>2</sub> S <sub/>3</sub> Semiconductors
摘要： 2D magnetic materials have attracted intense attention as ideal platforms for constructing multifunctional electronic and spintronic devices. However, most of the reported 2D magnetic materials are mainly achieved by the mechanical exfoliation route. The direct synthesis of such materials is still rarely reported, especially toward thickness-controlled synthesis down to the 2D limit. Herein, the thickness-tunable synthesis of nanothick rhombohedral Cr2S3 flakes (from ≈1.9 nm to tens of nanometers) on a chemically inert mica substrate via a facile chemical vapor deposition route is demonstrated. This is accomplished by an accurate control of the feeding rate of the Cr precursor and the growth temperature. Furthermore, it is revealed that the conduction behavior of the nanothick Cr2S3 is variable with increasing thickness (from 2.6 to 4.8 nm and >7 nm) from p-type to ambipolar and then to n-type. Hereby, this work can shed light on the scalable synthesis, transport, and magnetic properties explorations of 2D magnetic materials.
关键词： Cr2S3,chemical vapor deposition,controlled growth,conduction type transition
更新于2025-09-12 10:27:22
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Large‐Scale Fabrication of Highly Emissive Nanodiamonds by Chemical Vapor Deposition with Controlled Doping by SiV and GeV Centers from a Solid Source
摘要： A new strategy to produce loose chemical vapor deposited nanodiamonds (ND) without the need of a seeded substrate, and that are intentionally doped by silicon vacancy and GeV centers from a solid source is presented. The addition of a low amount of gases such as N2 or O2 during growth is used as a control knob to finely tune the emission intensity of embedded color centers. NDs with a high brightness and a controllable amount of group IV color centers are eventually obtained. Their optical properties at low temperature indicate that this approach can usefully produce dispersed NDs that can deliver suitable optical performance for quantum technologies.
关键词： nanodiamond,color centers,quantum technologies,spectroscopy,chemical vapor deposition
更新于2025-09-12 10:27:22
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Self-catalyzed growth of GaSb nanowires for high performance ultraviolet-visible-near infrared photodetectors; 自催化生长GaSb纳米线及其在高性能紫外-可见-近红外光电探测器中的应用;
摘要： A simple self-catalyzed chemical vapor deposition process was conducted to synthesize single-crystalline GaSb nanowires, where Ga droplets were utilized as the catalysts. The as-grown GaSb nanowires exhibited typical p-type semiconductor behavior with the calculated hole mobility of about 0.042 cm2 V?1 s?1. The photoresponse properties of the GaSb nanowires were studied by fabricating nanowire photodetectors on both rigid and flexible substrates. The results revealed that the photodetectors exhibited broad spectral response ranging from ultraviolet, visible, to near-infrared region. For the device on rigid substrate, the corresponding responsivity and the detectivity were calculated to be 3.86×103 A W?1 and 3.15×1013 Jones for 500 nm light, and 7.22×102 A W?1 and 5.90×1012 Jones for 808 nm light, respectively, which were the highest value compared with those of other reported Ga1?xInxAsySb1?y structure nanowires. Besides, the flexible photodetectors not only maintained the comparable good photoresponse properties as the rigid one, but also possessed excellent mechanical flexibility and stability. This study could facilitate the understanding on the fundamental characteristics of self-catalyzed grown GaSb nanowires and the design of functional nano-optoelectronic devices based on Gasb nanowires.
关键词： photoresponse,GaSb nanowires,chemical vapor deposition,mobility,near-infrared,flexible
更新于2025-09-12 10:27:22
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Hydrophobic surface modification toward highly stable K2SiF6:Mn4+ phosphor for white light-emitting diodes
摘要： K2SiF6:Mn4+ phosphor is well known for its excellent red emission performance which is vital for improving the color rendering of white light-emitting diodes. However, the poor moisture resistance limits its application in optical devices. In this paper, K2SiF6:Mn4+ phosphor is coated with an inorganic hydrophobic protective layer to obtain good moisture resistance. Chemical vapor deposition method was used to decompose acetylene at high temperature, and the generated nanoscale carbon layer worked as a hydrophobic protective coating on the surface of the phosphor. Microstructure, compositions and properties of the synthesized K2SiF6:Mn4+@C phosphor were investigated in detail. It is found that most of the deposited carbon is coated on the surface of phosphor crystals in amorphous state. The carbon atoms are bonded with the fluorine element in K2SiF6:Mn4+ phosphor, forming carbon-fluorine (C?F) covalent bonds. The moisture resistance of K2SiF6:Mn4+@C phosphor is improved owing to the protection of the hydrophobic carbon. The relative emission intensity of K2SiF6:Mn4+@C phosphor could maintain 73% of the initial luminous intensity after immersing in the aqueous solution at room temperature for 8 hours, whereas K2SiF6:Mn4+ phosphor without carbon coating was only 0.7% remaining of the initial value under the same conditions.
关键词： Moisture-resistant,Chemical vapor deposition,K2SiF6:Mn4+,Carbon coating
更新于2025-09-12 10:27:22
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Inlaid ReS <sub/>2</sub> Quantum Dots in Monolayer MoS <sub/>2</sub>
摘要： Two-dimensional (2D) transition metal dichalcogenides (TMDs) are prospective materials for quantum devices owing to their inherent 2D confinements. They also provide a platform to realize even lower-dimensional in-plane electron confinement, e.g., 0D quantum dots, for exotic physical properties. However, fabrication of such laterally confined monolayer (1L) nanostructure in 1L crystals remains challenging. Here we report the realization of 1L ReS2 quantum dots epitaxially inlaid in 1L MoS2 by a two-step chemical vapor deposition method combining with plasma treatment. The lateral lattice mismatch between ReS2 and MoS2 leads to size-dependent crystal structure evolution and in-plane straining of the 1L ReS2 nanodots. Optical spectroscopies reveal the abnormal charge transfer between the 1L ReS2 quantum dots and the MoS2 matrix, most likely resulting from electron trapping in the 1L ReS2 quantum dots. This study may shed light on the realization of in-plane quantum-confined devices in 2D materials for potential applications in quantum information.
关键词： chemical vapor deposition,phase transition,2D materials,phase engineering,transition metal dichalcogenide alloy
更新于2025-09-12 10:27:22
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Highly self-oriented growth of (020) and (002) monoclinic HfO2 thick films using laser chemical vapor deposition
摘要： Monoclinic hafnia (m-HfO2) films were prepared on polycrystalline AlN substrates via thermal and laser chemical vapor deposition (thermal CVD and laser CVD). Highly self-oriented growth of (020) and (002) m-HfO2 films was demonstrated at a high deposition rate. Films prepared using thermal CVD exhibited a porous microstructure and no preferred orientation, whereas those prepared using laser CVD exhibited significant proportions of (020) and (002)-oriented m-HfO2. The (020) and (002) orientations were observed to be as high as 90% and 98%, respectively. The (002)-oriented m-HfO2 film exhibited a columnar structure with a feather-like texture in cross-section, and with a pyramidal faceted surface. Deposition rates of the (002)-oriented m-HfO2 films reached 67 μm h?1, approximately 40 times greater than previously reported, thermal-CVD-grown m-HfO2 films.
关键词： Films,Chemical vapor deposition,Oriented growth,Monoclinic HfO2
更新于2025-09-12 10:27:22
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Single-Source Vapor-Deposited Cs2AgBiBr6 Thin Films for Lead-Free Perovskite Solar Cells
摘要： Lead-free double perovskites have been considered as a potential environmentally friendly photovoltaic material for substituting the hybrid lead halide perovskites due to their high stability and nontoxicity. Here, lead-free double perovskite Cs2AgBiBr6 films are initially fabricated by single-source evaporation deposition under high vacuum condition. X-ray diffraction and scanning electron microscopy characterization show that the high crystallinity, flat, and pinhole-free double perovskite Cs2AgBiBr6 films were obtained after post-annealing at 300°C for 15 min. By changing the annealing temperature, annealing time, and film thickness, perovskite Cs2AgBiBr6 solar cells with planar heterojunction structure of FTO/TiO2/Cs2AgBiBr6/Spiro-OMeTAD/Ag achieve an encouraging power conversion efficiency of 0.70%. Our preliminary work opens a feasible approach for preparing high-quality double perovskite Cs2AgBiBr6 films wielding considerable potential for photovoltaic application.
关键词： perovskite solar cell,lead-free,thin film,single-source vapor deposition
更新于2025-09-12 10:27:22