二维原子晶体锑烯和二硒化铂的制备和物性

发布时间：2018-04-25 08:44

本文选题：二维原子晶体 + 锑烯　；参考：《中国科学院大学(中国科学院物理研究所)》2017年博士论文

【摘要】：随着电子工业的发展,集成度的提高,电子器件的尺寸需要进一步缩小,因此人们在探寻新材料的同时,也在不断降低电子材料的尺寸和维度。自从2004年,石墨烯被成功的剥离制备以来,二维材料受到了人们的广泛关注。石墨烯优异的性能,如高热导率,超高载流子迁移率等,使得石墨烯在未来电子学领域具有广泛的应用潜力,同时也激励着人们探索更多具有优异性能的二维材料。近年来,单元素类石墨烯材料(如硅烯,锗烯等)以及层状过渡金属二硫属化合物(TMDs,如二硫化钼)等,以其自身优异的物理化学性质,成为了材料科学界的研究热点,受到广泛关注。本论文主要工作集中于锑烯,一种新型类石墨烯二维原子晶体,以及二硒化铂,一种新型层状过渡金属二硫属化合物。利用分子束外延的手段对其进行制备,通过低能电子衍射,扫描隧道显微镜,自旋极化扫描隧道显微镜,X射线光电子能谱等表征手段结合第一性原理计算,对其物理性质及结构特性进行研究。(1)锑烯(Antimonene),一种新型二维原子晶体被预言具有优良的光电子学和自旋电子学性质,而引起了人们的极大关注。本文的第一部分主要介绍了过渡金属二硫属化合物二碲化钯表面制备和研究单层锑烯的工作。通过晶格匹配筛选,选择了二碲化钯作为衬底,来尽可能缩小衬底与锑烯的晶格失配程度。在生长过程中,在对衬底进行加热的同时沉积高纯锑单质,从而得到二维有序的单层锑烯。利用原位扫描隧道显微镜及低能电子衍射,观察到在二碲化钯上,锑烯是(1×1)生长,可以得到清晰的蜂窝状结构原子分辨。同时利用X射线光电子能谱结合第一性原理计算,揭示了锑烯的二维原子结构以及和衬底的弱相互作用。进一步,将锑烯暴露空气之后,再利用原位STM和XPS测量,探测了锑烯在空气中的化学稳定性,揭示了其在未来实际电子器件应用中的巨大潜力。(2)二维材料中的一维结构,如边界和纳米带等一直是人们研究的热点,关于二维材料边界的磁学性质,相关的理论工作层出不穷,但实验上的工作却很稀少,还有大量未解决的问题。本文的第二部分主要介绍了利用自旋极化扫描隧道显微镜对二硒化铂(PtSe_2)纳米带边界自旋进行测量的工作。利用直接硒化的方法,在Pt(111)基底上生长了PtSe_2纳米带。利用扫描隧道显微镜结合第一性原理计算,能够确定纳米带边界的构型。同时,利用扫描隧道显微谱在实空间的分布,研究了其边界处的能带弯曲,证明了纳米带边界处未饱和的化学环境。进一步,进行了使用镍针尖的自旋极化扫描隧道显微镜实验,在实验上观察到在相反的磁场下,同一边界上扫描隧道显微谱的信号不同,更深一步,从谱图上也可清晰地得到在边界处的信号对比。结合使用普通扫描隧道显微镜的对照试验,在实验上首次直接观测到了PtSe_2纳米带边界上的自旋结构,即在同一边界上自旋一致,同时由于其中心反演对称性,观测到纳米带的两条对边自旋相反。该实验结果对未来二维材料边界及相关其在自旋电子学中的应用及研究具有重要的意义。(3)PtSe_2作为一种新型过渡金属二硫属化合物材料,其单层材料以高迁移率和宽带隙成为了近年来新兴的研究热点。本文的第三部分主要集中在以为石墨为衬底生长单层及双层PtSe_2,并对其体态及边界处本征能隙进行测量。利用分子束外延的方法,成功在石墨上制备了单层及双层PtSe_2岛。利用低温扫描隧道谱,从实验上首次对单层和双层二硒化铂的本征能隙进行了测量,精确地观察到了单层和双层PtSe_2的本征带隙。同时,实验中也测量了能隙在单层边界处的分布,揭示了边界处能带弯曲的现象。更进一步地,测量了单层和双层界面处的能隙分布情况,发现了界面处某些能带消失。结合第一性原理计算,成功揭示了PtSe_2层间轨道对能隙的影响,进一步解释了单双层PtSe_2能隙差别的来源,揭示了其与二硒化钼等传统六重对称过渡金属二硫属化合物层间作用的差别。对于二维材料层间作用的研究在二维半导体物性调控领域具有重要意义,是将来二维材料走向应用过程中十分重要的一步。
[Abstract]:With the development of the electronics industry and the improvement of the degree of integration, the size of the electronic devices needs to be further reduced. As a result, the size and dimension of the electronic materials are constantly reduced while people are exploring new materials. Since the successful peeling of graphene in 2004, the two-dimensional material has attracted wide attention. Such as high thermal conductivity and ultra-high carrier mobility, graphene has a wide application potential in the field of electronics in the future, and it also encourages people to explore more excellent properties of two-dimensional materials. In recent years, single element graphene materials (such as Silene, germanium, etc.) and layered transition metal two sulfur compounds (TMDs, such as two) Molybdenum sulfide, and so on, has become a hot topic in the field of material science for its excellent physical and chemical properties. It has been focused on antimonene, a new type of graphene like two-dimensional atomic crystal, two selenide platinum, a new type of lamellar transition gold, two sulfur compounds. By means of low energy electron diffraction, scanning tunneling microscope, spin polarized scanning tunneling microscope, X ray photoelectron spectroscopy and other characterization methods, the physical properties and structural properties are studied. (1) antimonene (Antimonene), a new type of two-dimensional atomic crystal is predicted to have excellent optoelectronics and self. The first part of this paper mainly introduces the preparation and study of the monolayer antimonene on the surface of the transition metal two sulphur compound, two palladium telluride, and selected two palladium telluride as substrate by lattice matching, to reduce the lattice mismatch between the substrate and antimonene as much as possible. During the process, the high pure antimony monomer was deposited while the substrate was heated. The two-dimensional ordered monolayer antimonene was obtained. Using in situ scanning tunneling microscope and low energy electron diffraction, it was observed that on two palladium telluride, antimonene was (1 x 1) growth, and a clear honeycomb structure could be obtained by atomic resolution. At the same time, X ray photoelectron spectroscopy was used to combine. The first principle calculation reveals the two-dimensional atomic structure of antimonene and the weak interaction with the substrate. Further, after exposing the air to antimonene, the chemical stability of antimonene in the air is detected by the in-situ STM and XPS measurements, and the great potential in the future application of the actual electronic devices is revealed. (2) one dimension in the two-dimensional material. Structures, such as boundary and nanoscale, have always been a hot spot of research. The theoretical work on the magnetic properties of the two-dimensional material boundary is emerging, but the work in the experiment is very few, and there are still a lot of unsolved problems. The second part of this paper mainly introduces the use of spin polarized scanning tunneling microscopy (SPM) for the two selenide platinum (PtSe_2). PtSe_2 nanoribbons were grown on the Pt (111) substrate by direct selenide. Using the scanning tunneling microscope combined with the first principle, the configuration of the nanoscale boundary could be determined. At the same time, the band bending of the boundary was studied by the distribution of the scanning tunneling microscope in the real space. The unsaturated chemical environment at the boundary of the nanoscale is proved. Further, the spin polarization scanning tunneling microscope (SPM) experiment using the nickel tip is carried out. In the experiment, it is observed that the signal of scanning tunnel microspectrum on the same boundary is different under the opposite magnetic field, and the signal contrast at the boundary can be clearly obtained from the spectrogram. The spin structure on the PtSe_2 nanoscale boundary is directly observed in a controlled experiment using a common scanning tunneling microscope (SCM) for the first time. That is, the spin on the same boundary is consistent. At the same time, because of its central inversion symmetry, the two opposite spin of the nanobelts are observed. The experimental results are related to the boundary and correlation of the future two-dimensional material. Its application and research in spintronics are of great significance. (3) PtSe_2 as a new type of transition metal two sulfur compounds, its single layer material has become a new research hotspot in recent years with high mobility and wide band gap. The third parts of this paper mainly focus on the growth of monolayer and double layer PtSe_2 on graphite as the substrate, and The intrinsic energy gap at the body and the boundary is measured. By using the method of molecular beam epitaxy, the monolayer and double PtSe_2 islands are prepared successfully on the graphite. By using the low temperature scanning tunneling spectroscopy, the intrinsic gap of two selenide platinum in single layer and double layer is measured for the first time, and the intrinsic band gap of single layer and double layer of PtSe_2 is observed accurately. At the same time, the distribution of the energy gap at the single layer boundary is measured and the phenomenon of the band bending at the boundary is revealed. Further, the distribution of the energy gap at the single layer and the double layer interface is measured, and some energy bands at the interface are found to disappear. The effect of the PtSe_2 interlayer orbit on the energy gap is successfully revealed by the first principle. Further, the effect of the interlayer orbit on the gap is further revealed. The source of the gap difference between the single and double layers of PtSe_2 is explained, and the difference between the interlayer action of the traditional six heavy symmetric transition metal two sulfur compounds, such as molybdenum selenide, is revealed. The study on the interlayer action of two dimensional material is of great significance in the field of two-dimensional semiconductor property control, and is very important in the application of the two-dimensional material in the future. A step.

【学位授予单位】：中国科学院大学(中国科学院物理研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O48

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