Study On The Properties Of Adsorption Of Adatoms On Single-layer Phosphorene Of Novel Two-dimensional Semiconducting Materials

Adsorption of adatoms on surface is one of the most effective ways to change the physical and chemical properties of semiconductor. Metal adatoms or nonmetal adatoms are adsorbed on the surface of singlr- layer phosphorene, which changes its band structure, electronic density of states, electronic structure, and optical properties. The features of phosphorene with adatoms adsorbed on surface are different form phosphorene, especially the changes of electric conductivity and manetic properties. Based on Quantum Mechanics and Density Functional Theory, First Principles Calculations is a comparatively effective way to study the properties and change of microstructure of materials with adatoms adsorbed on its surface, which further studies the electronic and micro geometric structure of phosphorene materials, theoretically attests the correctness of some experimental phenomena, explores unknown features of them to develop new materials.The research of the thesis can be mainly divided into following parts:The first part studies the atomic and electronic structure and magnetic properties of phosphorene. Singlr- layer phosphorene, whose structure is orthorhombic structure and space group is C mca( No.64), is a typical two-dimensional semiconductor with direct bandgap. In terms of theory, the thesis specifically analyzes the band structure and electronic density of states of it. The rightness of physical properties of phosphorene has been proved.The second part studies the basic physical properties of the following atoms: C、N、O、Na、Mg、Al, including the most favorable adsorption sites, geometric structure and electron transfer, and systematically analyzes the results. There is a strong interaction between adatom and phosphorene with larger adsorption energy. When nonmetal adatoms are adsorbed on the surface of phosphorene, P atom is covalently bonded to nonmetal adatoms with strong interactions.When metal adatoms are adsorbed on the surface of phosphorene, structurally more stable than graphene, electrons are transferred from metal to it, which play a positive role in phosphorene as battery electrode.Finally, after adatoms adsorbed on the surface of phosphorene are analyzed, it has been proved that its band structure and electronic density of states vary with energy. For different adatoms adsorbed, the thesis calculates their figures of band structure, total density of states and partial density of states, and analyzes the sources of density of states of phosphorene according to its stages. In terms of calculation, when N、Na、Al are adsorbed, phosphorene material, direct bandgap semiconductor, turns into conductor. when C is adsorbed, it, whose system is special and affected by spin magnetism, turns into fake conductor. when Mg is adsorbed, the system remians with smaller gap than phosphorene. With Mg, its system, direct bandgap semiconductor, turns into indirect bandgap semiconductor. When O is adsorbed, its system remians, because band strcture and are hardly influenced by O, whose band structure is similar to phosphorene. Through systematic analysis of the system of phosphorene, it can be found that why adatom adsorption changes the properties of phosphorene are the interactions between different adatoms and different electron transfer, which can be used as effecitve data for deep-seated study of phosphorene...