Future information technologies require low power, high performance transistors, and the future of the international semiconductor technology roadmap describes the future transistor channel length less than 10 nanometers.
One of the hot research topic in recent years the two-dimensional (2 d) atomic crystal materials compared with the traditional semiconductor material, with scattered small, high mobility, is advantageous for the preparation of the laminated heterogeneous structure, easy control of electrical properties, one of an excellent candidate materials for future transistor.
Found in the two-dimensional atomic crystal materials, composed of the periodic table IV group elements single-layer material (such as graphene, silicon, germanium and tin material, etc.) with high carrier mobility, but because of its band gap to zero or near zero, restricts their application foreground of electronics, such as mosfet device.
In contrast, layered materials composed of V elements in the periodic table of the elements, such as black phosphorus, have the characteristics of large bandgap and high carrier mobility.
However, black phosphorus is unstable in atmospheric conditions, and the applicability of the devices it makes is limited.
More recently, antimonene, a single layer of antimonene, has intrigued researchers.
The theory predicts that the bandgap of antimonene will change with the thickness of the layer, especially for the mon-layer antimonene, and the theory predicts that the band gap will be 2.28 eV.
At the same time, compared with graphene, antimonene has higher carrier mobility.
Based on these characteristics, antimonene has potential applications in related electronic devices and optoelectronic devices.
Therefore, how to obtain this kind of material, especially the high quality single layer antimonene growth is closely watched.
Member of Chinese academy of sciences, Chinese academy of sciences/Beijing condensed matter physics, institute of physics, national research center researcher hong-jun gao team, over the years committed to the new two-dimensional crystal materials preparation, properties and application of basic research, has made a series of research results.
In recent days, the research team's doctoral student wu xu, shao yan and researcher wang yiliang, etc., have prepared mono-layer antimonene and have studied its structure and characteristics.
In the analysis of photoelectron spectroscopy, the research team cooperated with the deputy researcher of the Beijing synchrotron radiation center.
In terms of theoretical calculation, they cooperated with sun jiatao, the associate researcher of physics.
The monocrystalline substrate of palladium (PdTe2) is provided by the physics researcher shi youguo.
In the process of concrete experimental design, researchers consider the transition metal disulfide belong to families of the layered compounds (TMD) PdTe2 surface chemical properties stable, at the same time with the six-party symmetry, lattice period and antimony (4.10 A) single crystal layer within the cycle (4.12 A) lattice mismatch, antimony and the predictions of the theory of single olefinic cycle (4.01 A) lattice mismatch degree is only 2.3%.
Therefore, they chose PdTe2 as the substrate and used the molecular beam epitaxial growth method to obtain high quality single - layer antimonene.
Using low energy electron diffraction (LEED) and scanning tunneling microscopy (STM), on the growth of antimony monolayer on the fine structure of atoms, figure can be clearly distinguished from STM antimony atoms formed hexagonal honeycomb structure, for antimony material;
The LEED experiment showed that they obtained a large, high-quality monocrystalline single crystal (figure 1).
Combined with X-ray photoelectron spectroscopy experiment and electronic LAN function theory calculation results, reveals the monolayer antimony LAN electronic state between the basement and rarely, only weak van der Waals interaction (figure 2, figure 3).
Further STM and XPS experimental observation results show that (figure 4), single antimony in air with high chemical stability, has not been oxidation after exposure to air, this feature is vital for antimony ene to get closer to the actual application.
This work provides a method of preparation of high quality single antimony ene, also provides a preparation of two-dimensional material of atomic level interface of heterostructure new way of thinking, namely direct use of TMD materials as the substrate epitaxial single two-dimensional atomic crystal materials, for the study of the two-dimensional material heterojunction devices provide valuable reference.
At the same time, antimony, as a kind of graphene structure of new two-dimensional atomic crystal materials, expand the non carbon two-dimensional cellular crystal material field of study, and it has the characteristics of broadband gap, high mobility, stability in atmospheric environment, the electronic device has potential application prospect in the future.
The results were published on Advanced Materials.
The study was supported by the national natural science foundation, the ministry of science and technology and the Chinese academy of sciences.
(source: institute of physics, Chinese academy of sciences)
Figure 1. Monoatomic layer antimonene with epitaxial growth.
Monolayer growth PdTe2 surface antimony diagram (a), a wide range of STM images and LEED diffraction spots (b), atomic resolution STM figure (c) and the corresponding lateral plane graph (e, f), and atomic structure top view and side view (d).
Figure 2. Atomic structure model (a, d) of single layer of antimonene on surface of PdTe2 surface, corresponding STM simulation image (b), experimental image (c), electronic local function top view and tangent plane (e, f).
Figure 3. PdTe2 antimony monolayer growth substrate surface before and after the olefinic Pd and XPS measurements of Te elements (a, b), single Sb elements in antimony ene (c), the measurement results of XPS show that between substrate and antimony single olefinic almost no charge transfer.
Figure 4. Test of chemical stability of single layer of antimony.
Combined experiments with STM (a, b, c) and XPS (d) show that single - layer antimonene does not change after exposure to air, showing excellent chemical stability.
东莞杰夫 三氧化二锑