Effect of residual gas on the optoelectronic properties of Mg-doped Ga0.75Al0.25N (0 0 0 1) surface
Effect of residual gas on the optoelectronic properties of Mg-doped Ga0.75Al0.25N (0 0 0 1) surface
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DOI：
10.1016/j.apsusc.2021.149455
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发表时间：
2021-06
影响因子：
6.7
通讯作者：
Fang Qianglong-;Shen Yang;Xiaodong Yang;Shuqin Zhang;Liang Chen;L. Duan;Shangzhong Jin
中科院分区：
文献类型：
--
作者：
Fang Qianglong-;Shen Yang;Xiaodong Yang;Shuqin Zhang;Liang Chen;L. Duan;Shangzhong Jin
为了验证残余气体分子（H2，CH 4，CO，H2O和CO2）吸附在Mg掺杂的Ga 1-xAlxN（0 0 0 1）表面上的影响，计算了吸附体系的光电性质.通过第一性原理计算，分析了表面吸附能、功函数、偶极矩、费米能级、真空能级、能带、态密度和吸收系数。计算结果表明，CO、H2O和CO2分子的吸附模型均为物理稳定结构。然而，H2和CH 4的吸附在室温下可能不稳定。CO2分子最容易附着在阴极表面，并导致功函数的显著增加。残余气体捕获由阴极表面产生的部分电子，然后产生从阴极表面指向残余气体分子的偶极矩。此外，在残气吸附体系中还观察到了能带的微小变化。由于轨道运动，在深能带中也产生了一些新的能级。CO、H_2O和CO_2分子的吸附对吸收系数也有显著影响。
In order to verify the effect of residual gas molecules (H2, CH4, CO, H2O and CO2) adsorbing on the Mg-doped Ga1-xAlxN (0 0 0 1) surface, the photoelectronic properties of the adsorption systems are calculated. Through the first-principles calculation, the surface adsorption energy, work function, dipole moment, the Fermi and vacuum levels, the energy bands, density of states and absorption coefficients are analyzed. The calculation results demonstrate that the adsorption models of CO, H2O, and CO2molecules are all physically stable structures. However, the adsorption of H2and CH4may not be stable at room temperature. CO2molecule is the most easily attached to the cathode surface and results in a significantly increasement of the work function. The residual gas captures part of the electrons generated by the cathode surface, and then produces a dipole moment directing from the cathode surface to the residual gas molecules. In addition, tiny alteration of energy band is observed on the residual gas adsorption system. Due to the orbital motion, some new energy levels are also generated in the deep energy band. Moreover, the adsorption of CO, H2O and CO2molecules also exert a noticeable effect on the absorption coefficient.