镧系掺杂ZnO的电子结构和光学性质

Electronic Structure and Optical Properties of Lanthanide Doping ZnO

通过第一性原理计算研究了镧系元素掺杂ZnO的电子结构和光学性质。结果表明:单层ZnO中掺杂形成能低于体ZnO的形成能。较Zn原子而言,具有更大原子半径的镧系原子的引入使得掺杂后的ZnO的晶格常数变大。镧系元素的4f电子与O的2s和Zn的3p、4s轨道电子的杂化使非磁性的ZnO在掺入单个镧系原子后呈现出一定的铁磁性。镧系元素掺杂ZnO使体系的价带和导带之间出现了杂质能级,这使带隙减小从而提高了ZnO的导电能力;Eu/La/Ce掺杂ZnO的光吸收谱在近红外区域出现了新的吸收峰。随Eu/Ce-Oi双缺陷的形成,氧间隙明显地改变了ZnO的光学性质。

The electronic structure and optical properties of lanthanide doping ZnO are investigated by firstprinciples calculation.The formation energy of lanthanide doping in SL(single-layer)-ZnO structure that is lower than in bulk-ZnO structure.The magnetism of ZnO will change along with single lanthanide atom doping from nonmagnetic to ferromagnetic,which roots in orbital hybridization of 4f of lanthanide,O-2p and Zn-3p and-4s.Impurities level formed in CBM(conduction-band minimum)or VBM(valence-band maximum)along with lanthanide doped will reduce the band gap and improve the conductivity of materials.For Eu/La/Ce doping ZnO,new absorbing peak will be formed in infrared regions,and Eu/Ce-Oi double defects will obviously improve its optical properties.