Epitaxial Growth And Properties Of New Two-dimension Materials-Borophene And Phosphorene

Since transistors were discovered,the semiconductor industry has developed rapidly and great changes have taken place in our daily life.As computer and the mobile device have evolved,the chips with higher quality are needed.It is necessary to improve the integrated circuit density,to reduce the volume of the device and the power dissipation.For these reasons the structure and technology of the device must be improved,and new material is another choice.In 2004,graphene was discovered,which opened the door of the two-dimensional material for it has many advantages compared to the others.In recent years,more and more researchers concerned about the two-dimensional materials,it is believed that they have great application prospects in electronics,optoelectronics and other fields.However,there is no two-dimensional material that can be directly applied to the semiconductor industry.The aims of the thesis are to explore the growth method of high-quality two-dimensional boron and phosphorus by using MBE,and study their electronic properties by the STM,as follows:1.By using the method of MBE,growing the two-dimensional boron on the surface of Ag(111),two structures phase S1 and phase S2 were presented which respectively matched the theoretical predictions of model ?12 and model ?3.There are two other new structures phase S3 and phase S4 under the condition of 570k.Phase S3 has the same atomic structure with phase S1(structure ?12)while its relative substrate has different tangle from that of phase S1,thus their STM images did not show the same.And phase S4 is the relative structure of hexagonal symmetry,and it is confirmed a-sheet,predicted by theoretical calculation.All four different phases are metallic by STS technology.2.Making a simply phosphorus evaporation source,the two-dimensional phosphorus on the surface of the Ag(111)has been growing by using the method of MBE.It is shown that its defects decrease as the temperature increases.The atomic structure and lattice constant of the two-dimensional phosphorus are showed by STM,and it is confirmed blue phosphorene.