位错在纳米线生长中的作用
发布时间：2019-01-05 17:17
【摘要】：一维纳米材料的生长机制研究是生长控制,结构与性能的基础。螺位错驱动生长机制是提出于上世纪50年代,用于解释晶体的一维生长,然而在有限的实验条件下,纳米线中的螺位错不容易被确认。由于实验技术的发展,螺位错驱动生长机制在2008年之后再次受到广泛的关注。本文着重研究CuO和Zn S纳米线生长过程中位错的作用,主要内容如下:第一,通过热氧化法制备了CuO纳米线,研究了温度和冷却方式对CuO纳米线生长的影响。600℃空冷样品只长出了少量CuO纳米线,600℃炉冷样品上观察到了大量CuO纳米线,400℃空冷样品上也生长了大量CuO纳米线,表明CuO纳米线的实际生长温度不高于400℃。温度比较高时,以CuO层的生长为主;在温度比较低时,以CuO纳米线的生长为主。这一结果可以通过铜离子在氧化层中的扩散过程来理解。第二,电子显微结构分析显示,氧化铜纳米线为多重孪晶结构,并发现纳米线生长方向上存在螺位错,其螺位错的柏氏矢量为[110]方向。铜氧化过程的应力和缺陷导致多重孪晶结构的产生,多重孪晶结构中的应力又导致了纳米线中的螺位错的产生,螺型位错推动纳米线的生长。第三,在ZnS纳米线中,研究发现层错导致生长方向由[01-10]转变为[0001]。孪晶也能改变纳米线的生长方向,但不改变纳米线晶体生长取向。在硫化锌纳米线中存在着不全位错,不全位错露头处的台阶可以作为台阶源与螺位错一样驱动晶体的一维生长。
[Abstract]:The growth mechanism of one-dimensional nanomaterials is the basis of growth control, structure and properties. The mechanism of screw dislocation driven growth was proposed in the 1950s to explain the one-dimensional growth of crystal. However, under limited experimental conditions, the screw dislocation in nanowires is not easy to be confirmed. With the development of experimental technology, the mechanism of snail dislocation driven growth has been paid more and more attention since 2008. The effect of dislocation on the growth of CuO and Zn S nanowires is studied in this paper. The main contents are as follows: firstly, CuO nanowires were prepared by thermal oxidation. The effects of temperature and cooling mode on the growth of CuO nanowires were studied. Only a small amount of CuO nanowires were grown in air-cooled samples at 600 鈩，
本文编号：2402076
[Abstract]:The growth mechanism of one-dimensional nanomaterials is the basis of growth control, structure and properties. The mechanism of screw dislocation driven growth was proposed in the 1950s to explain the one-dimensional growth of crystal. However, under limited experimental conditions, the screw dislocation in nanowires is not easy to be confirmed. With the development of experimental technology, the mechanism of snail dislocation driven growth has been paid more and more attention since 2008. The effect of dislocation on the growth of CuO and Zn S nanowires is studied in this paper. The main contents are as follows: firstly, CuO nanowires were prepared by thermal oxidation. The effects of temperature and cooling mode on the growth of CuO nanowires were studied. Only a small amount of CuO nanowires were grown in air-cooled samples at 600 鈩，
本文编号：2402076
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