Preparation method for large-size ultrathin bismuth selenide nanosheet

Abstract

The invention discloses a preparation method-vapor phase transmission method for a large-size ultrathin bismuth selenide (Bi2Se3) nanosheet. The preparation process includes the following steps: 1) according to a molar ratio of 2:3, weighing a certain amount of a bismuth powder and a selenium powder, cleaning a Si / SiO2 substrate and a quartz tube, and adhering the substrate on a quartz block with a high temperature resistant glue; 2) putting the raw materials of the bismuth powder and the selenium powder into one end of the quartz tube, vertically putting the other end of the quartz tube into the Si / SiO2 substrate, vacuumizing the quartz tube, and sealing; 3) putting the quartz tube into a high-vacuum tube furnace, according to a certain heating rate, carrying out heat preservation for a certain time at a set temperature, and then cooling along with the furnace; and 4) taking out and cutting apart the quartz tube, and thus obtaining the Si / SiO2 substrate grown with the Bi2Se3 nanosheet. The method adopts the high-purity bismuth powder and the high-purity selenium powder as the raw materials, and synthesis is carried out under the high temperature and high vacuum conditions, and thus the obtained Bi2Se3 nanosheet has good crystallinity and high purity, and has wide application prospects in the fields of optoelectronic devices, thermoelectric condensing units and the like.

Description

technical field [0001] The present invention relates to Bi 2 Se 3 The preparation method is a large-scale ultra-thin bismuth selenide Bi 2 Se 3 Nanosheet preparation method. Background technique [0002] Bi 2 Se 3 It has a bismuthite structure and belongs to the hexagonal crystal system. It is a new type of topological insulator material with surface conduction and internal insulation. It has excellent photoelectric performance, thermoelectric performance and rectification effect, and is widely used in optoelectronic devices and thermoelectric condensation devices. Bi 2 Se 3 It has a layered structure like graphene, and it is composed of structural units called quintuples. Each quintuple structural unit contains 5 atoms and is connected by covalent bonds. The arrangement is as follows: Se-Bi-Se-Bi -Se and quintuple are connected by van der Waals force, so they are easily dissociated along the interlayer to form a sheet structure. Theoretical calculations and experim...

AI Technical Summary

Problems solved by technology

However, the nanosheets prepared by these methods are generally small in size and large in thickness, and some have poor uniformity and many impurity phases, which are limited when applied to nanodevices.