理论研究半金属TiB_(2)的电子结构和光学特性

THE ELECTRONIC STRUCTURE AND OPTICAL PROPERTIES OF TIB_(2)

为了系统地分析半金属TiB_(2)的能带结构及光学特性,采用密度泛函理论的第一性原理平面波赝势方法,计算分析了TiB_(2)的电子结构及光学特性。能带结构表明TiB_(2)具有直接带隙宽度为0.388 eV的半金属材料,在费米能级附近,态密度的价带主要由Ti的3p价电子和B的2p价电子起作用,导带由Ti的3d价电子起主要贡献。从获得的光学特性参数发现在光子能量为0.73 eV处,Ti的4s3p和B的2p电子发生共振,复介电函数的峰值主要出现在低能区,材料对紫外光的最大吸收系数为4.03×10^(5)cm^(-1)。本研究得到的光学特性参数在光电子器件、微电子和紫外探测器等制作方面有着较好的参考作用。

In order to systematically analyze the energy band structure and optical properties of semi-metallic TiB_(2),the electronic structure and optical properties of TiB_(2)are calculated by using the first-principles plane wave pseudopotential method of density functional theory.The energy band structure indicates that TiB_(2)has a semiconductor material with a direct band gap width of 0.388 eV.Near the Fermi level,the valence band of density of states is mainly affected by 3p valence electrons of Ti and 2p valence electrons of B,and the conduction band is mainly contributed by 3d valence electrons of Ti.From the obtained optical characteristic parameters,it is found that at the photon energy of 0.73 eV,the 4s3p of Ti and the 2p electron of B resonate.The peak value of complex dielectric function appears in the low-energy region.The maximum absorption coefficient of the material to ultraviolet light is 4.03×10^(5) cm^(-1).The optical characteristic parameters obtained in this paper have a good reference function in the fabrication of optoelectronic devices,microelectronics and ultraviolet detectors.