We present an Al2O3 dielectric layer on molybdenum disulfide (MoS2), deposited using atomic layer deposition (ALD) with ozone/trimethylaluminum (TMA) and water/TMA as precursors. The results of atomic force microscopy and low-energy ion scattering spectroscopy show that using TMA and ozone as precursors leads to the formation of uniform Al2O3 layers, in contrast to the incomplete coverage we observe when using TMA/H2O as precursors. Our Raman and X-ray photoelectron spectroscopy measurements indicate minimal variations in the MoS2 structure after ozone treatment at 200 °C, suggesting its excellent chemical resistance to ozone.

Two olefinic blocky copolymers (OBCs) were quenched from different mixing states in the melt, and crystallization kinetics and morphology at various crystallization temperatures (T cs) and corresponding mechanical properties were studied. It is observed that, at lower T cs, premesophase separation in the melt accelerates crystallization of OBC-A with a weak segregation strength and a larger fraction of the crystalline hard blocks due to enrichment of the hard blocks in the hard-block-rich domains. By contrast, premesophase separation retards crystallization of OBC-B with a stronger segregation strength and lower fraction of the hard blocks because of the prevailing confinement effect at lower T cs. Moreover, since the hard blocks dissolved in the soft-block-rich domains can crystallize at lower T cs, which can bridge the crystals formed in different hard-block-rich domains, the crystal growth is not restricted. At higher T cs, OBC-A crystallizes more slowly from the premesophase-separated melt than that from the homogeneous melt, which is attributed to the weaker crystallizability of the hard blocks dissolved in the soft-block-rich domains and thus the restricted crystal growth. Nevertheless, mesophase separation always takes place prior to crystallization at higher T cs for OBC-B because of the faster rate of mesophase separation. Therefore, the mixing state in the melt has little effect on crystallization and morphology of OBC-B at higher T cs. It is found that the mechanical properties of OBCs can be regulated in a wide range by alteration of crystallization conditions. Better mechanical properties can be achieved when OBCs crystallize from the homogeneous melt and at a lower T c.

Recently, there are significant progresses in the growth of organic-inorganic lead halide perovskite single crystals, however, due to their susceptible nucleation and growth mechanisms and solvent requirements, the efficient and generalized growth for these single crystals is still challenging. Here we report the work towards this target with a polymer-controlled nucleation process for the highly efficient growth of large-size high-quality simple ternary, mixed-cations and mixed-halide perovskite single crystals. Among them, the carrier lifetime of FAPbBr3 single crystals is largely improved to 10199 ns. Mixed MA/FAPbBr3 single crystals are synthesized. The crucial point in this process is suggested to be an appropriate coordinative interaction between polymer oxygen groups and Pb2+, greatly decreasing the nuclei concentrations by as much as 4 orders of magnitudes. This polymer-controlled route would help optimizing the solution-based OIHPs crystal growth and promoting applications of perovskite single crystals.

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The Earth's topography generally obeys fractal statistics; after either one‐ or two‐dimensional Fourier transforms the amplitudes have a power law dependence on wave number. The slope gives the fractal dimension, and the unit wave number amplitude is a measure of the roughness. In this study, digitized topography for the state of Arizona (7 points/km) has been used to obtain maps of fractal dimension and roughness amplitude. The roughness amplitude correlates well with variations in relief and is a promising parameter for the quantitative classification of geomorphology. Significant variations in fractal dimension are also found. For Arizona the mean fractal dimension for two‐dimensional Fourier spectral analyses is D = 2.09; for one‐dimensional Fourier spectral analyses the mean fractal dimension is D = 1.52, close to the Brown noise value D = 1.5. Synthetic two‐dimensional images have also been generated for a range of D values. For D = 2.1, the synthetic image has a mean one‐dimensional spectral fractal dimension D = 1.56, consistent with our results for Arizona. These results are also consistent with those of previous authors and show that it is not appropriate to subtract one from the two‐dimensional fractal dimension of topography in order to obtain the one‐dimensional fractal dimension.