激子
密度泛函理论
材料科学
辐射传输
导带
激发态
凝聚态物理
过渡金属
吸光度
结合能
基态
光电子学
原子物理学
物理
化学
计算化学
光学
量子力学
电子
催化作用
生物化学
作者
Minglei Sun,Michele Re Fiorentin,Udo Schwingenschlögl,Maurizia Palummo
标识
DOI:10.1038/s41699-022-00355-z
摘要
Abstract Semiconducting two-dimensional materials with chemical formula MoSi 2 X 4 (X = N, P, or As) are studied by means of atomistic ground- and excited-state first-principles simulations. Full-fledged quasi-particle bandstructures within the G 0 W 0 approach substantially correct the electronic bandgaps previously obtained with hybrid-functional density functional theory and highlight the absence of lateral valleys close in energy to the conduction band minimum. By solving the Bethe–Salpeter equation, we show that the optical properties are dominated by strongly bound excitons with the absorbance and maximum short-circuit current densities of MoSi 2 P 4 and MoSi 2 As 4 comparable to those of transition metal dichalcogenides. Due to the presence of the outer SiX layers, the exciton binding energies are smaller than those generally found for transition metal dichalcogenides. Long radiative lifetimes of bright excitons, over 10 ns at room temperature for MoSi 2 As 4 , and the absence of band-nesting are very promising for application in efficient ultra-thin optoelectronic devices.
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