论文标题
$ ab $ $ $ unitio $氢动力学和空隙的形态在无定形硅中
$Ab$ $initio$ hydrogen dynamics and the morphology of voids in amorphous silicon
论文作者
论文摘要
本文在密度功能理论的框架内介绍了纳米尺寸$ a $ a-si内部氢动力学研究的$ ab $ $ $ intio $研究，分别在400 k和700 k的低温和高温下的氢负载分别为10至30 h原子/空体。使用局部密度近似及其广义梯度对应物，对空隙内的氢原子的动力学进行了检查，以强调H原子/分子的扩散以及空隙表面的纳米结构变化。模拟的结果表明，空隙表面上的氢分布的微观结构和空隙的形态的特征是存在大量的一氢化物Si-H键，以及一些二氢二氢SI-H $ _2 $构型。该研究还表明，空隙内的大量（约10--45个at。％）的总H原子可以显示为H $ _2 $分子，氢负荷为10--30 h原子/void。通过凸 - 壳近似以及Si和H原子的伪原子表面的高斯拓宽，从对空隙表面原子的位置的了解来解决空隙的近似形状。
This paper presents an $ab$ $initio$ study of hydrogen dynamics inside nanometer-size voids in $a$-Si within the framework of the density-functional theory for a varying hydrogen load of 10 to 30 H atoms/void at the low and high temperature of 400 K and 700 K, respectively. Using the local density approximation and its generalized-gradient counterpart, the dynamics of hydrogen atoms inside the voids are examined with an emphasis on the diffusion of H atoms/molecules, and the resulting nanostructural changes of the void surfaces. The results from simulations suggest that the microstructure of the hydrogen distribution on the void surfaces and the morphology of the voids are characterized by the presence of a significant number of monohydride Si-H bonds, along with a few dihydride Si-H$_2$ configurations. The study also reveals that a considerable number of (about 10--45 at.%) total H atoms inside voids can appear as H$_2$ molecules for a hydrogen load of 10--30 H atoms/void. The approximate shape of the voids is addressed from a knowledge of the positions of the void-surface atoms using the convex-hull approximation and the Gaussian broadening of the pseudo-atomic surfaces of Si and H atoms.
