Investigation Of Structural And Electronic Properties Of Doping ZnO And INP Semicondutor

Diluted magnetic semiconductors (DMS) with room temperature ferromagnetism have attracted a great attention in the past decade due to its potential application in new generation of spintronic devices, now there are many studies on ZnO nanowires produced by being doped with transition metals (TMs). InP is a kind of important Ⅲ-Ⅴ semiconductor, which has some excellent characteristics such as high energy conversion efficiency, low-bandgap and high electron mobility, etc. These features make it a promising optoelectronic material in many field.In this paper, the main works are about doping ZnO and InP semiconductor, as follows:1. We perform a first-principles simulation to calculate and analyze systematically the magnetic properties of Vanadium dopd H-passivated ZnO nanowires. In this part, we discuss total density of state (TDOS) and partial density of state (PDOS), respectively. When we analyze the DOS, we find a fierce hybridization between V3d and O2p states appears at the Fermi level, which is found to be responsible for the FM coupling. Meanwhile, a half metallic in nature is found in V-doped ZnO NWs, which is ideal for injection of spin polarized charge carriers into the nonmagnetic system. Besides, the uniaxial strain is taken into account, the AE changes differently with the increase of the compressive and tensile strain in disparate configurations, so it is proved to have important influence on the magnetic properties of H-passivated V-doped ZnO NWs, and offers an effective method to devise a high curie temperature DMS. Our theoretical results indicate that V-doped ZnO NW has good magnetic properties which display diverse magnetic couplings.2. We mainly investigate the electronic structure of Bi doped InP semiconductor and some influencing factor, all structural optimizations, electronic and optical properties are performed based on the density functional theory. We consider every possible site of doping Bi so that make some models to compare, calculate formation energy, and then study the DOS and charge density plot of InPBi. In this process, we still calculate DOS and charge density plot of pure InP to compare with InPBi with increasing Bi concentration, and find that the fierce sp-hybridization becomes small between In and P, while the Bi-6p bands hybridize with In-4s band in the energy ranging from-5.6eV to-4.0eV, resulting in a weaker bonding between In and P. The bandgaps of InPBi alloys shrink clearly with the increasing Bi concentration. SOC effect is introduced and a shift of the band edge is observed with the increasing of Bi concentrations. Finally, the biaxial strain is taken into account and a transition from indirect to direct semiconductor can be obtained for InPBi alloys.