Department of Physics and Astronomy, Texas Tech University, Lubbock, TX, 79409, USA.
Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, 79409, USA.
Sci Rep. 2023 May 22;13(1):8260. doi: 10.1038/s41598-023-34721-8.
Understanding the relationship between surface adsorbates and secondary electronic emission is critical for a variety of technologies, since the secondary electrons can have deleterious effects on the operation of devices. The mitigation of such phenomena is desirable. Here, using the collective efforts of first-principles, molecular dynamics, and Monte Carlo simulations, we studied the effects of a variety of carbon adsorbates on the secondary electron emission of Cu (110). It was demonstrated that the adsorption of atomic C and C[Formula: see text] pair layers can both reduce and increase the number of secondary electrons depending on the adsorbate coverage. It was shown that under electron irradiation, the C-Cu bonds can be dissociated and reformed into C[Formula: see text] pairs and graphitic-like layers, in agreement with experimental observation. It was verified that the lowest secondary electron emission was due to the formation of the graphitic-like layer. To understand the physical reason for changes in number of secondary electrons for different systems from an electronic structure perspective, two-dimensional potential energy surfaces and charge density contour plots were calculated and analyzed. It was shown that the changes are strongly influenced by the Cu surface morphology and depends highly on the nature of the interactions between the surface Cu and C atoms.
了解表面吸附物与二次电子发射之间的关系对于各种技术至关重要，因为二次电子会对设备的运行产生有害影响。因此，减轻这种现象是可取的。在这里，我们利用第一性原理、分子动力学和蒙特卡罗模拟的集体努力，研究了各种碳吸附物对 Cu(110)二次电子发射的影响。结果表明，原子 C 和 C[Formula: see text]对层的吸附都可以根据吸附剂覆盖率减少和增加二次电子的数量。结果表明，在电子辐照下，C-Cu 键可以被解离并重新形成 C[Formula: see text]对和类石墨层，这与实验观察一致。验证了最低的二次电子发射是由于形成了类石墨层。为了从电子结构的角度理解不同体系中二次电子数量变化的物理原因，计算并分析了二维势能面和电荷密度等高线图。结果表明，这些变化受到 Cu 表面形态的强烈影响，并且高度依赖于表面 Cu 和 C 原子之间相互作用的性质。
