基于石墨烯的范德瓦尔斯异质结电子结构调制的研究
发布时间：2018-11-15 19:45
【摘要】：自从2004年英国科学家安德烈·盖姆和康斯坦丁·诺沃肖洛夫从石墨片上成功剥离出石墨烯以来。石墨烯因其独特的物理和化学特性,例如,整数量子隧道效应、超大的理论比面积,优异的导电特性和超高的电子迁移率及高的杨氏模量,成为了21世纪最具潜力的二维纳米材料。此外,也正是由于石墨烯的发现,在材料科学研究领域内引起了二维材料研究热潮。然而,二维材料虽然拥有体材料无法比拟的优异特性,但是它们在实际应用中却存在着许多限制。以石墨烯为例,石墨烯具有超高的电子迁移率,但是它的带隙为零,这就限制了它在电子器件工程的应用。本论文主要是应用基于密度泛函理论的第一性原理方法来理论分析石墨烯和砷烯、石墨烯和二硫化锡范德瓦尔斯异质结以及对其电子结构的调制,主要内容如下:1)对砷烯和石墨烯范德瓦尔斯异质结电子结构调制的研究,首先作为基础参数我们研究了石墨烯和砷烯的晶格参数和电子结构,并以此为基础,构建了砷烯和石墨烯的范德瓦尔斯异质结。通过对异质结的计算分析,我们发现当层间距离从2.8?增加到4.5?,石墨烯狄拉克点的位置和费米能级从砷烯的价带顶向导带底发生转移,且在转移过程中,p型肖特基势垒转变为n型肖特基势垒。通过进一步的分析研究,我们还发现可以通过改变砷烯和石墨烯异质结层间距离,来调控肖特基接触的势垒高度。此外,我们还构建了一种对称的三层石墨烯和砷烯范德瓦尔斯异质结结构,并简单分析了其电子结构和电场条件下对异质结的电子结构的调制效应。计算结果表明,三层异质结中电荷从砷烯转移到了石墨烯,并在界面处进行重排。同时,异质结的电子结构在电场的调节作用下,变化并不明显,这也说明对称的三层异质结的电子结构对电场的调控作用不敏感。2)对石墨烯和二硫化锡的范德瓦尔斯异质结电子结构调制的研究,研究发现层间距离和电场都可以有效的调节异质结的电子结构。当异质结层间距离增大(2.5?~4.4?)时,肖特基势垒的势垒有小幅度的减小,基本保持不变,这与范德瓦尔斯力作用效果一致。在外加电场的调节作用下,当施加负向电场时,石墨烯的狄拉克点的位置和费米能级从二硫化锡的导带向价带移动,势垒高度有小幅度的增加。当施加正向电场时,石墨烯的狄拉克点和费米能级进入二硫化锡的导带,形成欧姆接触。
[Abstract]:Since British scientists Andre Gheim and Constantine Novoschlov successfully stripped graphene from graphite wafers in 2004. Graphene is due to its unique physical and chemical properties, such as integer quantum tunneling effect, large theoretical specific area, excellent conductivity, high electron mobility and high Young's modulus, It has become the most potential two-dimensional nanomaterials in the 21 st century. In addition, the discovery of graphene has caused a wave of two-dimensional materials research in the field of material science. However, although two-dimensional materials have more excellent properties than bulk materials, they have many limitations in practical application. Taking graphene as an example, graphene has high electron mobility, but its band gap is zero, which limits its application in electronic device engineering. In this paper, the first principle method based on density functional theory is used to analyze graphene and arsenene, graphene and tin disulfide van der Waals heterojunction and their electronic structure modulation. The main contents are as follows: 1) the modulation of the electronic structure of arsenene and graphene van der Waals heterojunction is studied. Firstly, as the basic parameters, we study the lattice parameters and electronic structure of graphene and arsenene. The van der Waals heterojunction of arsenene and graphene was constructed. Through the calculation and analysis of the heterojunction, we find that when the interlayer distance is from 2. 8 to 2. 8? The position of the Dirac point of graphene and the Fermi level are transferred from the bottom of the valence band of arsenene to the bottom of the leading band. During the transfer process, the p-type Schottky barrier changes to the n-type Schottky barrier. Through further analysis we also found that the barrier height of Schottky contact can be regulated by changing the distance between the heterojunction of arsenene and graphene. In addition, we have constructed a symmetric three-layer graphene and arsenene van der Waals heterojunction structure, and analyzed the modulation effects of the electronic structure and electric field on the heterojunction electronic structure. The results show that the charge in the three-layer heterojunction is transferred from arsenene to graphene and rearranged at the interface. At the same time, the electronic structure of heterojunction does not change obviously under the regulation of electric field. It also shows that the electronic structure of symmetric three-layer heterojunction is insensitive to the regulation of electric field. 2) the modulation of electronic structure of graphene and van der Waals heterojunction of tin disulfide is studied. It is found that both interlaminar distance and electric field can effectively regulate the electronic structure of heterojunction. When the interlayer distance between the heterojunction increases (2.5?) The barrier of Schottky barrier decreases by a small margin and remains unchanged, which is consistent with the effect of van der Waals force. When the applied electric field is applied, the position of Dirac point and Fermi level of graphene move from the conduction band of tin disulfide to the valence band, and the barrier height increases slightly. When the positive electric field is applied, the Dirac point and Fermi level of graphene enter the conduction band of tin disulfide and form ohmic contact.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O469
本文编号：2334267
[Abstract]:Since British scientists Andre Gheim and Constantine Novoschlov successfully stripped graphene from graphite wafers in 2004. Graphene is due to its unique physical and chemical properties, such as integer quantum tunneling effect, large theoretical specific area, excellent conductivity, high electron mobility and high Young's modulus, It has become the most potential two-dimensional nanomaterials in the 21 st century. In addition, the discovery of graphene has caused a wave of two-dimensional materials research in the field of material science. However, although two-dimensional materials have more excellent properties than bulk materials, they have many limitations in practical application. Taking graphene as an example, graphene has high electron mobility, but its band gap is zero, which limits its application in electronic device engineering. In this paper, the first principle method based on density functional theory is used to analyze graphene and arsenene, graphene and tin disulfide van der Waals heterojunction and their electronic structure modulation. The main contents are as follows: 1) the modulation of the electronic structure of arsenene and graphene van der Waals heterojunction is studied. Firstly, as the basic parameters, we study the lattice parameters and electronic structure of graphene and arsenene. The van der Waals heterojunction of arsenene and graphene was constructed. Through the calculation and analysis of the heterojunction, we find that when the interlayer distance is from 2. 8 to 2. 8? The position of the Dirac point of graphene and the Fermi level are transferred from the bottom of the valence band of arsenene to the bottom of the leading band. During the transfer process, the p-type Schottky barrier changes to the n-type Schottky barrier. Through further analysis we also found that the barrier height of Schottky contact can be regulated by changing the distance between the heterojunction of arsenene and graphene. In addition, we have constructed a symmetric three-layer graphene and arsenene van der Waals heterojunction structure, and analyzed the modulation effects of the electronic structure and electric field on the heterojunction electronic structure. The results show that the charge in the three-layer heterojunction is transferred from arsenene to graphene and rearranged at the interface. At the same time, the electronic structure of heterojunction does not change obviously under the regulation of electric field. It also shows that the electronic structure of symmetric three-layer heterojunction is insensitive to the regulation of electric field. 2) the modulation of electronic structure of graphene and van der Waals heterojunction of tin disulfide is studied. It is found that both interlaminar distance and electric field can effectively regulate the electronic structure of heterojunction. When the interlayer distance between the heterojunction increases (2.5?) The barrier of Schottky barrier decreases by a small margin and remains unchanged, which is consistent with the effect of van der Waals force. When the applied electric field is applied, the position of Dirac point and Fermi level of graphene move from the conduction band of tin disulfide to the valence band, and the barrier height increases slightly. When the positive electric field is applied, the Dirac point and Fermi level of graphene enter the conduction band of tin disulfide and form ohmic contact.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O469
【参考文献】
相关博士学位论文 前2条
1 孙红义;新型二维材料的声子输运与热机械性质的数值模拟[D];南京大学;2016年
2 张克难;二硫化钼二维材料及其异质结的制备和光电特性研究[D];中国科学院研究生院(上海技术物理研究所);2016年
，本文编号：2334267
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