论文标题
单壁MOS $ _2 $纳米管
Indirect-to-direct band gap crossover of single walled MoS$_2$ nanotubes
论文作者
论文摘要
使用密度函数理论，研究了单壁钼纳米管（MOS $ _2 $ nts）的电子结构作为直径的函数。 Our calculations show that the electronic structure near the band gap is sensitive to the NT diameter: armchair MoS$_2$ NTs act as indirect gap semiconductors for diameters up to approximately 5.0 nm, while armchair MoS$_2$ NTs with larger diameters act as direct gap semiconductors with band edges located in the vicinity of $k = 2π/3$.这一发现表明，具有大直径的MOS $ _2 $ NTS应表现出与2D单层MOS $ _2 $ sheets相似的光致发光。这个间接到独立的带隙交叉归因于$γ$点在小直径NTS中的价带峰的向上移位，这是由其管状结构引起的拉伸应变引起的。
Using density functional theory, the electronic structures of single walled molybdenum disulfide nanotubes (MoS$_2$ NTs) were investigated as a function of diameter. Our calculations show that the electronic structure near the band gap is sensitive to the NT diameter: armchair MoS$_2$ NTs act as indirect gap semiconductors for diameters up to approximately 5.0 nm, while armchair MoS$_2$ NTs with larger diameters act as direct gap semiconductors with band edges located in the vicinity of $k = 2π/3$. This finding implies that MoS$_2$ NTs with large diameters should exhibit similar photoluminescence to 2D monolayer MoS$_2$ sheets. This indirect-to-direct band gap crossover is ascribed to the upward shift of the valence band peak at the $Γ$ point in small diameter NTs, which is caused by the tensile strain resulting from their tubular structures.
