The Preparation Of Boron-based Nanomaterials And The Study Of Their Photoelectric Properties

As a brand-new elemental graphene-like 2-dimensional nanostructure,borophene has attracted attentions of researchers due to the unique properties of boron atoms and the abundant structures of borophene,and the great potential for their unique physical and chemical properties are expected.However,there are only a few reports for the successful synthesis of borophene,which are also limited in several types of structure,alternative methods of synthesis are urged to be explored.Under such situation,we notice the potential of boron halides,which have been widely employed in the usage of boron-doping,to be a candidate of boron source for the synthesis of boron-based nanomaterials.We thus commit to synthesize boron-based nanomaterials utilizing boron halides with facile methods,and efforts are made to assemble devices based on such boron-based nanomaterials to investigate their photoelectric properties.The studies are as follows:1.With boron bromide as boron source,pyrolysis is employed to synthesize amorphous boron nanosheets with a thickness of 5-10 nm per layer and a diameter of?1 mm.The pyrolysis can be underwent at the temperature as low as 400? and only last for 15 min.The as-synthesized boron nanosheets are assembled into photoelectric devices by typical photoetching procedure.With a bias voltage of 5 V,the assembled devices shows a light current of 1.5 nA under the radiation of 405 nm laser(1.66 mW),and a dark current of 0.5 nA.2.Pyrolysis is employed to the mixture of boron bromide and pre-synthesized hafnium trisulphide nanobelts,and boron-doping hafnium trisulphide(B-HfS3)nanobelts are successfully synthesized.Devices based on B-HfS3 nanobelts are assembled for the test of their photoelectric properties.The structure characterizations show that the boron clusters formed by the pyrolysis of boron bromide can be doped into the layer gaps of the crystal lattices of the hafnium trisulphide nanobelts,playing the role of electron traps.The carrier concentration in the B-HfS3 nanobelts can thus be controlled taking the advantage of the electron deficiency of boron.The aggregation of B-HfS3 nanobelts can help to improve the re-combination of photo-induced carriers by forming network structure.After doped by boron,the specific detectivity of 405 nm laser is improved by 10%.3.Iodine and boron powders are used to form intermediate product of boron iodide during the chemical vapour transport method.Different substrates are used for the deposition of boron nanostructures.After varying the substrates,the reaction temperature and the reaction time,boron nanostructure with good morphology can be successfully deposited onto MgO substrates and 3 nm Au/Si substrates.On the former substrates,boron sheets with thickness of 5-20 nm covering most of the surfaces of the substrates are attained;on the latter substrates,helical boron nanowires with diameters of about 30 nm are synthesized.?...