Synthesis Of Topological Insulator Sb₂Te₃ Nanomaterials And Preparation Of Photodetectors

With the novel characteristics of body insulation and surface conduction,three-dimensional topological insulator materials have become the forefront and hotspot of international research at this stage,providing an important opportunity for the preparation of new high-performance optoelectronic devices.As a member of three-dimensional topological insulator,antimony telluride(Sb₂Te₃)has a series of excellent characteristics,such as protected surface state,narrow bulk band gap and high surface carrier mobility,which brings potential advantages in the preparation of low loss and broadband photoelectric detection devices.The excellent properties of Sb₂Te₃ are closely related to its crystal microstructure.Different low dimensional nanostructures have different properties.Therefore,taking Sb₂Te₃ physical vapor deposition synthesis as the starting point,Sb₂Te₃ nanomaterials were synthesized and characterized by different processes,and the preparation and device performance of photodetector were studied based on the prepared materials.The main research contents of the thesis include the following parts:(1)Sb₂Te₃ nanoflakes and nanofilms were synthesized on AFM special mica and fluorophlogopite substrates by vapor deposition.The transverse-to-longitudinal size ratio of the prepared nanoflakes was 300.The nanofilms had good continuity and uniformity,and had an atomic stoichiometric ratio close to the theoretical value of Sb₂Te₃.(2)Sb₂Te₃ thin films with a thickness of 15 nm were prepared on n-type silicon wafer substrate by vacuum thermal evaporation to form Sb₂Te₃/n-Si photodetector.The prepared Sb₂Te₃ film has good continuity and uniformity.The photoelectric performance test of the device shows that the junction device structure brings a fast response speed of20 ms,but the response of the device is small,and the maximum response is 9.48 m A/W under 520 nm light.(3)Based on the principle of vapor deposition,Sb₂Te₃ based nanofilms with different microstructures were synthesized by Sn doping under different growth time.It was found that Sb_0.405Te_0.595 nanofilm synthesized after 40 min of growth has the highest quality and the best crystallinity.Then we prepared photodetectors based on Sb_0.405Te_0.595 nanofilm.The photodetector shows a wide spectral response of 405 nm to 4500 nm and a fast response speed.The maximum responsivity of the device under 520 nm light is 588 A/W,and the specific detectivity is up to 10~8 level.Finally,we fabricated photodetectors by preparing Sb_0.405Te_0.595 nanofilms on polyimide substrates.It is found that the photodetector has high flexibility and good stability under different bending radius and different bending times.In the thesis,Sb₂Te₃ nanomaterials are synthesized by different processes and photodetectors are prepared.The new applications of Sb₂Te₃ based materials in the field of photoelectric detection are explored,which provides a new idea for the realization of high-performance topological insulator optoelectronic devices.