ZnSe是Ⅱ-Ⅵ族重要的半导体材料,在常温常压下是闪锌矿结构,在高压下会发生相变转变为岩盐矿结构。将过渡金属离子掺杂在ZnSe晶体中可以有效获得中红外区域的激光增益介质和光电材料。主要研究了高压对Cr 2+掺杂ZnSe半导体材料性质的影响。基于密度泛函理论的第一性原理,计算了掺杂剂(Cr 2+)的引入对ZnSe相变压强的影响,以及高压环境下ZnSe和Cr 2+∶ZnSe晶体的电子结构、光学性能和力学性能的变化。Cr 2+掺杂降低了ZnSe从闪锌矿到岩盐矿结构的相变压强,并且掺杂浓度越高,相变压强越低。分析了ZnSe和Cr 2+∶ZnSe的电子结构和光学性能,高压下晶体由半导体性质转变为金属性质。环境压力和高压下计算得到的弹性常数均满足稳定性条件,验证了晶体结构的机械稳定性。同时,高压下晶体较大的体积模量、剪切模量和杨氏模量说明岩盐矿结构具有更大的硬度和更高的稳定性。

ZnSe is an important semiconductor material of II-VI group. It exhibits a zinc blende (ZB) structure at room temperature and pressure, and the phase transition into a rock salt (RS) structure occurs under high pressure. Doping transition metal ions (TM ²⁺) into the ZnSe crystal can effectively produce laser gain media and photoelectric materials in the mid-infrared region, which exhibit important research significance. This study mainly deals with the effect of high pressure on the properties of the Cr ²⁺-doped ZnSe semiconductors. Further, the effect of dopant (Cr ²⁺) on the phase transition pressure of ZnSe and the changes of electronic structures, optical properties, and mechanical properties of ZnSe and Cr ²⁺∶ZnSe are calculated under high pressure using the first-principles calculations based on the density functional theory. The introduction of the dopant (Cr ²⁺) reduces the phase transition pressure of ZnSe from ZB structure to RS structure, and this trend continues with a further increase in the doping concentration. The electronic structures and optical properties of ZnSe and Cr ²⁺∶ZnSe are evaluated under high pressure, and ZnSe is found to shift from exhibiting semiconductor properties to exhibiting metal properties under high pressure. The calculated elastic constants of the crystals satisfy the stability conditions under both ambient and high pressure. Meanwhile, the large bulk modulus, shear modulus, and Young's modulus of the crystal under high pressure indicate that the RS structure exhibits considerable hardness and stability and is remarkably resistant to deformation under external influences.