硅量子点表面掺氮的电子结构计算

本文在量子点表面掺入氮原子,用第一性原理方法模拟计算硅量子点（111）面上的电子结构.本文主要解决两个问题：（1）比较研究六种不同大小的量子点结构掺杂和未掺杂氮原子情况下的带隙宽度和电子态密度变化;（2）分别用广义梯度近似（GGA）和局域密度近似（LDA）两种不同的算法计算六种量子点结构的带隙宽度和态密度,并比较GGA和LDA算法的特点.计算结果发现：带隙随着量子点的尺度变小而展宽,这符合量子受限规律;在量子点表面掺杂氮原子会减小带隙宽度;重要的是发现LDA算法对局域态更加敏感.

The Electronic Structure's Calculations of Silicon Quantum Dots Doped Nitrogen on Surface

A nitrogen atom was doped into quantum dots on surface, and electronic structure of silicon quantum dots on surface（ 111 ） were simulated with the first-principles. The paper addressed two questions： （1） It comparative studied the band gap and the electron density of states of six different sizes of quantum dots structure doped and undoped nitrogen atom; （2） It calculated the band gap and the density of states of the six quantum dots structure with the generalized gradient approximation （GGA） and the local density approximation （LDA）, and compared the characteristics of LDA and GGA algorithm. The results show that： the band gap broaden as the size of the quantum dots becoming smaller, which conforms with the laws of quantum confinement; Quantum dots doped nitrogen on surface will decrease the band gap states by LDA algorithm is more sensitive than that by ; It is important that the calculated results of density of GGA.