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oe1(光电查) - 科学论文

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?? 中文（中国） ▾

  • Synthesis, characterization and modeling of self-assembled porphyrin nanorods

    摘要： Porphyrin nanorods were prepared by ion-association between free-base meso 5,10,15,20-tetrakis-(4-N-methylpyridinium)porphyrin cations and tetraphenylborate anions. The nanorods have variable lengths (up to a few micrometers long) and diameters (~50–500 nm). Their structure at the molecular level was elucidated by combining multinuclear solid state NMR spectroscopy, synchrotron X-ray powder diffraction and DFT calculations.

    关键词： DFT modeling,solid state NMR,NMR crystallography,nanorods,porphyrin,self-assembly

    更新于2025-09-11 14:15:04

  • Insight of surface treatments for CMOS compatibility of InAs nanowires

    摘要： A CMOS compatible process is presented in order to grow self-catalyzed InAs nanowires on silicon by molecular beam epitaxy. The crucial step of this process is a new in-situ surface preparation under hydrogen (gas or plasma) during the substrate degassing combined with an in-situ arsenic annealing prior to growth. Morphological and structural characterizations of the InAs nanowires are presented and growth mechanisms are discussed in detail. The major influence of surface termination is exposed both experimentally and theoretically using statistics on ensemble of nanowires and density functional theory (DFT) calculations. The differences observed between Molecular Beam Epitaxy (MBE) and Metal Organic Vapor Phase Epitaxy (MOVPE) growth of InAs nanowires can be explained by these different surfaces terminations. The transition between a vapor solid (VS) and a vapor liquid solid (VLS) growth mechanism is presented. Optimized growth conditions lead to very high aspect ratio nanowires (up to 50 nm in diameter and 3 micron in length) without passing the 410 °C thermal limit, which makes the whole process CMOS compatible. Overall, our results suggest a new method for surface preparation and a possible tuning of the growth mechanism using different surface terminations.

    关键词： nanowires,growth modeling,self-catalyzed growth,hydrogen preparation,density functional theory (DFT) modeling,III-V semiconductors on silicon,InAs

    更新于2025-09-04 15:30:14