Van Ngoc Hoang, Trang Trieu Quynh
Atomic Molecular and Optical Physics Research Group, Institute for Advanced Study in Technology, Ton Duc Thang University Ho Chi Minh City Vietnam
Faculty of Electrical and Electronics Engineering, Ton Duc Thang University Ho Chi Minh City Vietnam.
RSC Adv. 2025 Jun 6;15(24):19192-19203. doi: 10.1039/d5ra03236a. eCollection 2025 Jun 4.
In this study, the structural, electronic, and optical properties of pristine and doped two-dimensional germanene quantum dots (GeQDs) were systematically investigated using first-principles calculations based on density functional theory (DFT). The model systems consist of monolayer GeQDs comprising 37 Ge atoms with hydrogen-passivated edges, including pristine, carbon-doped, and silicon-doped configurations. All structures are found to be dynamically stable, exhibit non-magnetic metallic behavior, and show distinctive structural modifications upon doping. Notably, carbon doping significantly reduces the buckling height of the quantum dots due to its smaller atomic radius and higher electronegativity. Multi-orbital hybridization analysis reveals substantial changes in electronic orbital interactions, particularly in the Si-doped structure. Charge density difference analysis indicates that carbon atoms act as charge acceptors, while silicon atoms donate charge to the surrounding Ge lattice. Optical property calculations show strong anisotropic absorption behavior, with all configurations demonstrating pronounced absorption in the ultraviolet region and moderate absorption in the visible range. These findings suggest that pristine and doped GeQDs hold promise for applications in nanoscale electronic and optoelectronic devices, including ultraviolet photodetectors, plasmonic components, and next-generation integrated circuits.
在本研究中，基于密度泛函理论（DFT）的第一性原理计算系统地研究了原始和掺杂的二维锗烯量子点（GeQDs）的结构、电子和光学性质。模型系统由包含37个锗原子且边缘氢钝化的单层GeQDs组成，包括原始、碳掺杂和硅掺杂构型。所有结构均被发现是动态稳定的，表现出非磁性金属行为，并且在掺杂时显示出独特的结构变化。值得注意的是，由于碳原子的原子半径较小且电负性较高，碳掺杂显著降低了量子点的屈曲高度。多轨道杂化分析揭示了电子轨道相互作用的显著变化，特别是在硅掺杂结构中。电荷密度差分析表明，碳原子充当电荷受体，而硅原子向周围的锗晶格提供电荷。光学性质计算显示出强烈的各向异性吸收行为，所有构型在紫外区域均表现出明显的吸收，在可见光范围内表现出适度的吸收。这些发现表明，原始和掺杂的GeQDs在纳米级电子和光电器件中具有应用前景，包括紫外光探测器、等离子体组件和下一代集成电路。
