The adsorption behaviors of intrinsic graphene-like GaN (g-GaN) and transition metal (TM) atom-doped g-GaN on Cl₂ and CO gas molecules were systematically investigated using first-principles calculations based on density functional theory. The results show that the adsorption of both Cl₂ and CO on the intrinsic g-GaN was physisorbed, and since the adsorption energies of both systems were positive, it indicates that the systems are unstable. On the contrary, the adsorption energies of Cl₂ and CO upon adsorption on Fe- and Co-doped g-GaN were negative and small, and the adsorption system is stable. By analyzing the properties of the density of states, charge density difference, and energy band structure, it can be concluded that the introduction of transition metal atoms can effectively enhance the interaction between gas molecules and g-GaN.

为了探索AlN在光电器件的潜在应用，基于密度泛函理论，采用第一性原理计算了本征AlN和稀土元素La、Yb掺杂AlN体系的光电特性和磁性。计算结果表明：本征AlN的带隙为6.060 eV。掺入La和Yb后都在导带底产生了杂质能级，使得电子从价带到导带所需的激发能量更低，有利于光学跃迁，从而改善AlN的光学性能。Yb掺杂后自旋向上和自旋向下的价带发生了劈裂，说明Yb掺杂后产生了磁性。La、Yb替位掺杂AlN后，光吸收带边向左往低能方向移动，发生了红移现象。掺杂La和Yb后AlN体系的静态介电常数由4.63分别增大为5.14、280.44，说明掺杂之后增强了体系耐高压特性；静态折射率则由2.12分别增大为2.26、17.06，改善了AlN的光学性质。

The electronic structure, magnetic, and optical properties of two-dimensional(2D) GaSe doped with rare earth elements X (X=Sc, Y, La, Ce, Eu) were calculated using the first-principles plane wave method based on density functional theory. The results show that intrinsic 2D GaSe is a p-type nonmagnetic semiconductor with an indirect bandgap of 2.661 1 eV. The spin-up and spin-down channels of Sc-, Y-, and La-doped 2D GaSe are symmetric, they are non-magnetic semiconductors. The magnetic moments of Ce- and Eu- doped 2D GaSe are 0.908μ_B and 7.163μ_B, which are magnetic semiconductors. Impurity energy levels appear in both spin-up and spin-down channels of Eu-doped 2D GaSe, which enhances the probability of electron transition. Compared with intrinsic 2D GaSe, the static dielectric constant of the doped 2D GaSe increases, and the polarization ability is strengthened. The absorption spectrum of the doped 2D GaSe shifts in the low-energy direction, and the red-shift phenomenon occurs, which extends the absorption spectral range. The optical reflection coefficient of the doped 2D GaSe is improved in the low energy region, and the improvement of Eu-doped 2D GaSe is the most obvious.