Al，Mg掺杂GaN电子结构及光学性质的第一性原理研究

基于密度泛函理论，采用广义梯度近似方法，计算了Al，Mg掺杂的闪锌矿型GaN的电子结构和光学性质，分析了其电子态分布与结构的关系，给出了掺杂前后GaN体系的介电函数和复折射率函数.计算结果表明掺有Mg的GaN晶体空穴浓度增大，会明显提高材料的电导率，而Al掺杂GaN晶体的载流子浓度不变，只是光学带隙变宽；通过分析掺杂前后GaN晶体的介电函数和复折射率函数，解释了体系的发光机理，为GaN材料光电性能的进一步开发与应用提供了理论依据.通过比较可知，所得出的计算结果与现有文献符合得很好. 关键词： GaN晶体 电子结构 光学性质 掺杂

First-principles study on electronic structure and optical properties of Al and Mg doped GaN

The electronic structure and optical properties of pure and Al_and Mg-doped cubic-blende GaN have been studied based on the density functional theory and the generalized gradient approximation method. The relationship between the distribution of the electronic states and their structures has been analyzed.The dielectric function and the complex refractive index function on the doping GaN system have been obtained. The calculation results indicate that the hole concentration of Mg-doped GaN is increased and the Mg-doping markedly enhanced the conductivity of the material.But the carrier concentration of Al-doped GaN is not changed and optical bandgap is broadened.The mechanism of luminescence has been explained in terms of an analysis of the dielectric function and the complex refractive index function. It offers theoretical data for the design and application of GaN optoelectronic materials. By comparison, our results are in good agreement with that published in the literatures.