The Epitaxial Growth And Surface Structure Research Of Two-dimensional Antimonene

V-sulfur compounds and V-VI compound materials have many peculiar physical characteristics and thermoelectric properties.These materials have attracted highly attention of material scientists in basic material research and even thermoelectric device applications.In this paper,through the method of molecular beam epitaxy,Sb film was grown on the surface of the as-prepared Bi2Se3 thin film with a small beam rate under ultra-high vacuum condition?better than 1x10-9mbar?.The growth process was monitored by related instruments at the same time,focusing on the Sb epitaxial growth mode.Besides high-vacuum facility,we also preparation of Sb2Te3 films by using self-built vacuum tube furnace which was based on physical vapor deposition.Through continuous adjustment of the doping source material,most suitable source material to Sb2Te3 film doped with Se was found.Optimizing the experimental growth conditions was applied and continuous solid solution Sb2?Tex Se1-x?3 ternary alloy films was obtained.The structure and properties of the prepared films were analyzed and characterized using relevant test equipments.The specific works aresummarized as follows:1.By using molecular beam epitaxy,a ?-phase 3^1/2×3^1/2 reconstructed buffer layer of Bi was first epitaxially grown on the Si?111?-7×7 reconstructed surface,and then Bi2Se3 thin films were successfully epitaxially grown on the surface of the ?-phase 3^1/2×3^1/2 film.Reflecting high energy electron diffractometer and scanning tunneling microscope were used to observe the Bi2Se3 thin films prepare process and adjust relevant experimental conditions to obtain the Bi2Se3 thin films with smooth surfaces.By controlling the beam of the Sb source,the Sb atom was slowly deposited on the surface of the prepared Bi2Se3 thin film,and the growth process of the Sb atom in the Bi2Se3 thin film was studied by scanning tunneling microscopy.From the results of the scanning tunneling microscope,we found that the Sb atoms evaporated on the Bi2Se3 film were attracted by the steps on the surface of the Bi2Se3 film,and then grew along the steps direction of the Bi2Se3 film.But some of Sb atoms spontaneously nucleate and grow on the surface of Bi2Se3 thin films.Sb atoms mainly grew on the steps of Bi2Se3 thin films surface.2.The Sb2Te3 thin film was prepared on a hydrogen-passivated silicon substrate by using a vacuum tube furnace based on physical vapor deposition method.By optimizing the experimental conditions,Sb2Te3 thin film with good crystal quality can be prepared when the set temperature of the vacuum tube furnace is 465?,the argon gas flow rate is 0.3 SLM,and the substrate temperature is 390? to 430?.By optimizing the doping source material selection,the amount of source material and the growth temperature,the continuous solid solution Sb2?Tex Se1-x?3 ternary alloy films were finally prepared by co-evaporating the Sb2Se3 compound and the Sb2Te3 compound.The ratio of Te and the Se elements in the ternary alloy film are close to 1:1.The crystal structure,surface morphology and composition of the alloy films were analyzed by X-ray diffraction,scanning electron microscopy and X-ray energy spectrum analysis.From the test results,we found that the total surface area of the prepared thin films were rough and the orientation of the surface grains were disordered,which reflecting the polycrystalline morphology of the thin film.The ratio of the Sb content in the alloy thin film to the sum of the Te content and the Se content was close to 2:3,and the content of Te and the content of Se are in the vicinity of 1:1.