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- Hu, Cheng, et al.
(författare)
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Characterization of Ni(Si,Ge) films on epitaxial SiGe(100) formed by microwave annealing
- 2012
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 101:9, s. 092101-
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Tidskriftsartikel (refereegranskat)abstract
- Microwave annealing (MWA) is investigated as an alternative technique to rapid thermal processing with halogen lamp heating (RTP) for low-temperature silicide formation on epitaxially grown Si0.81Ge0.19 layers. Phase formation, resistivity mapping, morphology analysis, and composition evaluation indicate that the formation of low-resistivity NiSi1-xGex by means of MWA occurs at temperatures about 100 degrees C lower than by RTP. Under similar annealing conditions, more severe strain relaxation and defect generation are therefore found in the remaining Si0.81Ge0.19 layers treated by MWA. Although silicidation by microwave heating is in essence also due to thermal effects, details in heating mechanisms differ from RTP.
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| 5. |
- Sun, Weiyi, et al.
(författare)
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Impacts of major volcanic eruptions over the past two millennia on both global and Chinese climates: A review
- 2024
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Ingår i: Science China Earth Sciences. - 1674-7313 .- 1869-1897. ; 67, s. 61-78
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Forskningsöversikt (refereegranskat)abstract
- Major volcanic eruptions (MVEs) have attracted increasing attention from the scientific community. Previous studies have explored the climatic impact of MVEs over the past two millennia. However, proxy-based reconstructions and climate model simulations indicate divergent responses of global and China’s regional climates to MVEs. Here, we used multiple data from observations, reconstructions, simulations, and assimilations to summarize the historical facts of MVEs, the characteristics and mechanisms of their climatic impact, and directions for future research. We reviewed volcanic datasets and determined intensive MVE periods; these periods corresponded to the years 530–700, 1200–1460, and 1600–1840 CE. After tropical MVEs, a substantial cooling effect is observed throughout the globe and China on the interannual-interdecadal time scales but an inconsistent cooling magnitude is detected between reconstructions and simulations. In the first summer after tropical MVEs, a decrease in global and monsoonal precipitation is observed. In reconstructions and simulations, an increased precipitation is seen for the Yangtze River Basin, while large uncertainties in precipitation changes are present for other regions of China. Decadal drought can be induced by frequent eruptions and volcanism superimposed on low solar irradiation and internal variability. MVEs affect climate directly through the radiative effect and indirectly by modulating internal variability, such as the El Niño–Southern Oscillation (ENSO) and Atlantic Multidecadal Oscillation (AMO). However, changes in the phase, amplitude, and periodicity of ENSO and AMO after MVEs and the associated mechanisms remain controversial, which could account for model-reconstruction disagreements. Moreover, other internal variability, uncertainties in reconstruction methods and aerosol-climate models, and climate background may also induce model-reconstruction disagreements. Knowledge gaps and directions for future research are also discussed.
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| 6. |
- Xiong, Min, et al.
(författare)
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Tailoring Phase Purity in the 2D/3D Perovskite Heterostructures Using Lattice Mismatch
- 2022
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Ingår i: ACS Energy Letters. - : AMER CHEMICAL SOC. - 2380-8195. ; 7:1, s. 550-559
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Tidskriftsartikel (refereegranskat)abstract
- Although the fabrication of two-dimensional (2D)/three-dimensional (3D) halide perovskite heterostructures has been employed to balance the long-term stability and high efficiency of perovskite solar cells, the formation of metastable quasi-2D perovskites remains the most serious challenge. Here, we demonstrate that large lattice mismatch derived from halide and cation differences between 2D and 3D perovskites are key to avoiding the formation of unintended 2D phases in the preparation of 2D/3D bulk heterostructure because the phase transformation becomes less thermodynamically favorable. Specifically, by employing chloride 2D perovskite (PYA)(2) PbCl4 (PYA = propargylammonium) crystals into a 3D precursor solution, we achieve a phase-pure 2D/3D heterojunction with clean type-I band alignment, which exhibits greatly reduced charge recombination. Furthermore, the incorporation of alkyne perovskites is also shown to suppress iodine diffusion and formation due to their exceptional iodine capture capacity. The resultant 2D/3D heterostructured devices exhibited enhanced efficiencies and stabilities compared with their 3D counterparts.
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