硅表面纳米结构设计与计算

发布时间：2018-05-28 03:37

本文选题：Si表面 + Si纳米结构　；参考：《青岛大学》2017年硕士论文

【摘要】：本文采用第一性原理密度泛函方法计算研究了 Si(111)表面上几种不同形状的Si、Ge纳米结构、并研究了它们的电子结构及光学特性。对Si(111)表面上的Si纳米结构的计算结果表明,Si表面上不同形状的纳米结构的能量稳定顺序为:凹坑台纳米带岛状量子点悬浮量子点;光学性质的计算分析显示,表面经纳米结构修饰后,Si表面的光吸收均得到了增强,但未明显改变最强吸收峰的位置,最大吸收峰的位置都出现在紫外314 nm附近。在紫外区域,类金刚石类纳米结构在所设计的表面纳米结构中对Si(111)表面的光吸收增强的百分比最大,为30%;在可见光区域,Si_(14)@Si_(64)纳米结构对光吸收的增强最大,百分比达到67%。此外,我们在Si(111)表面上放置了不同形状的Ge纳米结构,计算结果表明,所放置的三种表面纳米结构的能量的稳定性顺序为:条形岛纳米带六边形岛。对其光学性质的计算结果显示,条形岛的光吸收强度要高于六边形岛结构和纳米带结构;表面加入了 Ge量子点之后,Si(111)衬底的吸收峰位置未变,但Ge纳米结构对Si表面的修饰降低了 Si表面的光吸收强度。
[Abstract]:In this paper, the first principle density functional method is used to calculate and study several kinds of SiGe nanostructures with different shapes on the surface, and their electronic structures and optical properties are also studied. The calculated results of Si nanostructures on Si (111) surface show that the order of energy stability of different shapes of nanocrystalline structures on Si surface is as follows: concave platform nanobantes island quantum dots suspended quantum dots, optical properties calculated and analyzed, The light absorption of Si surface modified by nanostructure was enhanced, but the position of the strongest absorption peak was not changed obviously, and the position of the maximum absorption peak appeared in the vicinity of UV 314 nm. In ultraviolet region, diamond-like carbon nanostructures have the largest percentage of enhancement of light absorption on Si _ (111) surface in the designed surface nanostructures (30%), while in the visible region, the enhancement of optical absorption of diamond-like carbon nanostructures is the largest (up to 67%) in the visible region. In addition, we have placed GE nanostructures with different shapes on the Si-111) surface. The calculated results show that the energy stability of the three surface nanostructures is in the order of hexagonal island. The calculated results of optical properties show that the optical absorption intensity of the strip island is higher than that of the hexagonal island structure and the nanoband structure, and the position of the absorption peak of the substrate is not changed after the addition of GE quantum dots on the surface. However, the modification of GE nanostructures on Si surface reduces the intensity of light absorption on Si surface.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O613.72

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