表面钝化效应对GaAs纳米线电子结构性质影响的第一性原理研究

发布时间：2018-04-25 07:38

  本文选题：GaAs纳米线 + 表面钝化　； 参考：《物理学报》2017年19期

【摘要】：纳米线表面存在大量的表面态,它们能够引起电子分布在纳米线表面,使得纳米线的电学性质对表面条件变得更加敏感,严重地制约器件的性能.表面钝化能够有效地移除纳米线的表面态,进而能够有效地优化器件的性能.采用基于密度泛函理论的第一性原理计算方法研究了表面钝化效应对GaAs纳米线电子结构性质的影响.考虑了不同的钝化材料,包括氢元素、氟元素、氯元素和溴元素.研究结果表明:具有小尺寸的GaAs裸纳米线的能带结构呈间接带隙特征,表面经过完全钝化后,转变为直接带隙特征;GaAs纳米线表面经过氢元素不同位置和不同比例钝化后,展示出不同的电学性质;表面钝化的物理机理是钝化原子与纳米线表面原子通过电荷补偿移除纳米线表面的电子态;与氢元素钝化相比,GaAs纳米线表面经过氟元素、氯元素和溴元素钝化后,带隙宽度较小,原因是氟元素、氯元素和溴元素在钝化过程中具有较小的电荷补偿能力,不能完全移除表面态.
[Abstract]:There are a large number of surface states on the surface of nanowires, which can cause electrons to distribute on the surface of nanowires, which makes the electrical properties of nanowires more sensitive to surface conditions and severely restricts the performance of devices. Surface passivation can effectively remove the surface state of nanowires and then optimize the device performance. The effect of surface passivation on the electronic structure of GaAs nanowires was studied by using the first principle method based on density functional theory. Different passivation materials were considered, including hydrogen, fluorine, chlorine and bromine. The results show that the energy band structure of the bare GaAs nanowires with small size exhibits indirect band gap characteristics. After the surface is completely passivated, the GaAs nanowire surface is transformed into a direct band gap feature. The surface of the GaAs nanowires is passivated by hydrogen elements at different positions and in different proportions. The physical mechanism of surface passivation is that the passive atoms and the surface atoms of nanowires remove the electronic states of the nanowires by charge compensation, and the surface of GaAs nanowires undergo fluorine in comparison with hydrogen passivation. After the passivation of chlorine and bromine, the band gap width is smaller, because fluorine element, chlorine element and bromine element have smaller charge compensation ability in the passivation process, and the surface state can not be completely removed.
【作者单位】： 湖南工学院数理科学与能源工程学院;广西师范学院物理与电子工程学院;
【基金】：国家自然科学基金(批准号:11704112,11547197,61640405,61704036) 湖南省自然科学基金(批准号:2017JJ3051,2017JJ2062) 湖南省教育厅科研项目(批准号:17B066,17B065,16A052) 衡阳市科技计划项目(批准号:2016KJ14) 湖南工学院大学生创新训练计划项目(批准号:HX1608) 湖南省大学生研究性学习和创新性实验计划项目资助的课题~~
【分类号】：TB383.1
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本文编号：1800431