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摘要单层MoS2是一种新的二文半导体材料，具有直接带隙等优良性能。本文主要考察了无缺陷的单层MoS2和有硫缺陷的单层MoS2作为气敏元件对气体吸附的敏感性。通过第一性原理计算，对所建的气体吸附模型进行了几何优化，算出气体吸附前后的能量变化，得出吸附能，电子状态密度，电导率，电荷密度等。分析计算的结果，主要结论如下：
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（1）有硫缺陷的单层 MoS2的气体分子优化前后位置比无缺陷的单层 MoS2气体吸附模型变化更大。有硫缺陷的单层 MoS2 的吸附能均小于吸附在无缺陷的单层MoS2上的吸附能。
（2）气体吸附后在费米面附近有态密度。 21594
（3）气体分子与单层MoS2之间有明显的电荷转移。 （4）无缺陷的单层 MoS2的带隙 Gap 为 1.649eV，有硫缺陷的单层 MoS2的 Gap为1.245eV。吸附气体分子后 Gap发生相应的改变。
毕业论文关键词 气体吸附 单层MoS2 硫缺陷 电导率 电荷转移 带隙
Title Simulation of two-dimensional semiconductor sulphide properties
Abstract
Single-layer MoS2 is a two-dimensional semiconductor material, has
excellent performance of direct band gap etc.. This paper mainly studied
the gas adsorption sensitivity of defect free monolayer MoS2 and sulfur
deficient monolayer MoS2 as a gas sensor. Among the first principle
calculation, the gas adsorption model has been geometry optimized and the
energy changes after gas adsorption, the adsorption energy, and electronic
state density, electrical conductivity, charge density have been
calculated. From the results of calculation, the main conclusions are as
following:
(1)Sulfur deficient monolayer MoS2 gas molecules change larger than
single-layer MoS2 gas adsorption model before and after optimization.
Adsorption energy on sulfur deficient monolayer MoS2 was less than
adsorption energy on defect free Single-layer MoS2.
(2)After the gas adsorption, the new density of states appeared near the
Fermi surface.
(3)The gas molecules adsorbed on the monolayer MoS2 has obvious charge
transfer between each other.
(4)The defect free Single-layer MoS2 has band gap 1.649eV, sulfur deficient
monolayer MoS2 has Gap 1.245eV. Gap changed after adsorption of gas molecules.
Keywords gas adsorption monolayer MoS2 sulfur defect
electrical conductivity charge transfer band gap
目 录
1. 引言. 1
1.1 MoS2的发展现状 1
1.1.1 石墨烯. 1
1.1.2 二文半导体材料.. 2
1.1.3 层状 MoS2 3
1.1.4 层状 MoS2材料的制备 .. 4
1.1.5 层状 MoS2材料的表征 .. 4
1.1.6 层状 MoS2材料的应用 .. 4
1.1.7 层状 MoS2在气体吸附方面的研究 . 5
1.1.8 目前研究中存在的问题.. 6
1.1.9 小结 6
1.2 第一性原理的基本介绍 . 6
1.2.1 量子力学.. 6
1.2.2 两个近似.. 7
1.2.3 两个定理.. 7
1.2.4 交换关联能 7
1.2.5 常用计算软件. 8
1.2.6 小结 8
1.3 本课题要研究或解决的问题和拟采用的研究手段（途径）： 9
1.3.1 要研究的问题. 9
1.3.2 拟采用的研究手段 9
1.3.3 小结 9
2. 计算方法与步骤.. 10