研究了单空位和双空位缺陷对碳化硅结构的影响.缺陷的存在明显地改变了碳化硅结构的带隙,C原子单空位缺陷转变为直接带隙半导体,带隙甚至减少到0.01 e V.通过对体系磁性的计算,我们发现Si原子的单空位缺陷和双空位缺陷均为体系带来了磁...研究了单空位和双空位缺陷对碳化硅结构的影响.缺陷的存在明显地改变了碳化硅结构的带隙,C原子单空位缺陷转变为直接带隙半导体,带隙甚至减少到0.01 e V.通过对体系磁性的计算,我们发现Si原子的单空位缺陷和双空位缺陷均为体系带来了磁性,磁性的产生主要是由于Si原子缺陷的存在使得缺陷周围的C原子在缺陷处产生了未成对电子,从而体系产生了磁性.展开更多
Previous calculations show that the two-dimensional (2D) silicon carbide (SiC) honeycomb structure is a structurally stable monolayer. Following this, we investigate the electronic properties of the hydrogen and fluor...Previous calculations show that the two-dimensional (2D) silicon carbide (SiC) honeycomb structure is a structurally stable monolayer. Following this, we investigate the electronic properties of the hydrogen and fluorine functionalized SiC monolayer by first-principles calculations. Our results show that the functionalized monolayer becomes metallic after semi-hydrogenation or semi-fluorination, while the semiconducting properties are obtained by the full functionalization. Compared with the bare SiC monolayer, the band gap of the fully hydrogenated system is increased, in comparison with the decrease of the gap in the fully fluorinated case. As a result, the band gap can be tuned from 0.73 to 4.14 eV by the functionalization. In addition to the metal-semiconductor transition, hydrogenation and functionalization also realize a direct-indirect semiconducting transition in the 2D SiC monolayer. These results provide theoretical guidance for design of photoelectric devices based on the SiC monolayer.展开更多
文摘研究了单空位和双空位缺陷对碳化硅结构的影响.缺陷的存在明显地改变了碳化硅结构的带隙,C原子单空位缺陷转变为直接带隙半导体,带隙甚至减少到0.01 e V.通过对体系磁性的计算,我们发现Si原子的单空位缺陷和双空位缺陷均为体系带来了磁性,磁性的产生主要是由于Si原子缺陷的存在使得缺陷周围的C原子在缺陷处产生了未成对电子,从而体系产生了磁性.
基金Supported by the Program for New Century Excellent Talents in Universities of China under Grant No NCET-09-0867
文摘Previous calculations show that the two-dimensional (2D) silicon carbide (SiC) honeycomb structure is a structurally stable monolayer. Following this, we investigate the electronic properties of the hydrogen and fluorine functionalized SiC monolayer by first-principles calculations. Our results show that the functionalized monolayer becomes metallic after semi-hydrogenation or semi-fluorination, while the semiconducting properties are obtained by the full functionalization. Compared with the bare SiC monolayer, the band gap of the fully hydrogenated system is increased, in comparison with the decrease of the gap in the fully fluorinated case. As a result, the band gap can be tuned from 0.73 to 4.14 eV by the functionalization. In addition to the metal-semiconductor transition, hydrogenation and functionalization also realize a direct-indirect semiconducting transition in the 2D SiC monolayer. These results provide theoretical guidance for design of photoelectric devices based on the SiC monolayer.
