The First-principles Study On New Nano-photoelectron Materials

Due to the small size, low dimensionality, quantum size effects and so on, nano-materials have unique physical and chemical properties. Theoretical studies have shown that the semiconductor type and the band gap of new nano-photoelectron materials represented by the III-V compound nanotubes can change with the change of nanotube configuration, expected to be used in high efficiency solar photovoltaic devices and optical sensors fields. In recent years, first-principles calculation based on density functional theory method has been widely used for condensed matter physics, materials science and quantum chemistry. Because of high efficiency, reliable results and able to overcome the limitations of experimental conditions and make up for lack of theory, this calculation has become a powerful research tool for the new nano-photoelectron materials.In the thesis, we use first principle calculation software VASP to construct different configurations of single-walledâ…¢-phosphide (boron phosphide, aluminum phosphide, gallium phosphide) nanotubes and then study the stability and electronic structure of them. The results showed that single-walledâ…¢-phosphide nanotubes are all in a metastable state. Zigzag nanotubes are direct band gap semiconductor, with band gap increasing with the diameter. The absorption photon energy range in the visible and infrared light. All these properties show that single-walled Ill-phosphide nanotubes have a good application prospect in photovoltaic devices and photoelectric converter. Then we construct graphene model and calculate the electronic structure of boron-doped and nitrogen-doped graphene, found that doping can significantly move the Fermi level, and have a major impact in changing the electrical properties.