|Alternative Title||Electronic properties of low dimensional phosphorene-related materials: A first principles study
|Place of Conferral||兰州
1. 对于锯齿型磷烯纳米带的电子能带结构受宽度调控明显，扶手椅型磷烯纳米带的电子结构对宽度效应并不敏感，带隙保持在1 eV附近。
2. 对于锯齿型磷烯纳米带用硼或碳来替代其中的磷原子，相当于少电子掺杂，在磷烯纳米带的电子结构费米处会出现杂质态，进而诱发带隙发生变化。相应的变化范围分别为1.27-1.87 eV和0.67-2.08 eV；而硫替代磷的情况，是多电子掺杂，带隙在0.57-2.20 eV之间进行调控。
3. 对于磷烯/硅烯的异质结构，界面处的磷原子会与硅烯中的硅原子形成sp3杂化，进而会形成层间共价键，使得异质结的带隙变窄，约为0.12 eV；考虑到电场的斯塔克效应在异质结中通常要比在单原子层中大，我们采用施加垂直电场来调节异质结的带隙。发现电场对带隙有明显的调控。
|Other Abstract||Carrier mobility and energy gap are key parameters to dominate a semiconductor material, which play an important role in practical applications of electronic devices. The former determines the power dissipation and switching speed, while the latter is a necessary condition to respond the external field. Thus, it is an intensive issue to obtain a good semiconductor material, which should simultaneously possesses a high carrier mobility and a proper band gap. Just recently, phosphorene, an atomic monolayer of black phosphorus, has attracted much research interest as it meets the above two criteria. The carrier mobility of phosphorene is theoretically predicted to be as high as 103-104 cm>2 which is comparable to graphene. More importantly, phosphorene has a direct band gap of around 1 eV at crystal momentum Γ, providing the possibility of device manipulation.
Motivated by the above mentions, in this thesis, we study how to modulate the band gap of phosphorene, aiming to extend its perspective applications, more detailed as follows. First, based on the quantum confinement effect and the edge states, we studied the band gap of phosphorene nanoribbons as a function of ribbons’ width. Second, particular elements, such as boron, carbon, and sulfur are doped in phosphorene nanoribbons. The results show that the impurity states are thus introduced, changing the electronic properties of phosphorene nanoribbons. Finally, we also investigated the heterostructure of phosphorene and silicone, and found that the silicene has a big effect on the band gap of phosphorene.
It is well known that phosphorene has a negative Poisson’s ratio, which can be applied in some special areas, such as national defense, medical, anti-seismic , when the layer number of arsenic reach four the negative tends to saturation which is the value of the bulk.|
韩建卫. 磷烯类低维材料的电子结构研究[D]. 兰州. 兰州大学,2016.
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