Mg单原子替位掺杂β-Ga_2O_3的电子结构和光学性质计算研究

An Investigation on the Electronic Structure and Optical Property of β-Ga_2O_3 Single Doped with Mg-substitution

宽禁带半导体β-Ga2O3因其出色的物理化学性能而备受关注,通过掺杂改善β-Ga2O3性能一直是研究的热点。采用基于密度泛函理论的第一性原理方法,利用广义梯度近似加U对Mg单原子掺杂β-Ga2O3体系的晶体结构、电子结构和光学性质等进行了研究和分析。总能量和结合能的对比显示:单原子替位掺杂β-Ga2O3时,Mg优先替代八面体位的Ga原子形成Mg-GaO体系。电子结构显示,Mg-GaO体系变为间接半导体,带隙变窄为4.672eV;其自旋极化率为100%,呈现半金属特性。作为光学材料,Mg-GaO体系可在紫外、深紫外区域工作,并且折射率、反射率和吸收率有所降低,透射率明显提高。

Wide bandgap semiconductor β-Oa2O3has attracted much attentions of researchers because of its ex- cellent physical and chemical properties and the efforts to improve the performance of β-Oa2O3 through doping other elements has been the hotspot of research programs. The crystal structure, electronic structure and optical property of Mg doped β-Oa2O33 were studied and analyzed by using GGA＋U scheme of first-principles calculation based on density functional theory. The contrast between the total energies and binding energies of two doping systems show that Mg atom is more inclined to replace the Ga atom at the octahedral site in single atom doping process resulting in Mg-Gao system. The electronic structure indicates that the system is an indirect semiconductor and its energy gap becomes nar- row, that is 4. 672 eV. The spin polarization of the system is 100%, showing its half metallic characters. As optical materials, Mg-Gao system can work in ultraviolet and deep ultraviolet regions with lower refractive index, refleetivity and absorption, as well as higher transmission rate. Therefore, Mg-Gao system can be used as diluted magnetic semi- conductor and ultraviolet transparency conductor materials.