Ramos Maria, Marques-Moros Francisco, Esteras Dorye L, Mañas-Valero Samuel, Henríquez-Guerra Eudomar, Gadea Marcos, Baldoví José J, Canet-Ferrer Josep, Coronado Eugenio, Calvo M Reyes
Departamento de Física Aplicada, Universidad de Alicante, Alicante 03690, Spain.
Instituto de Ciencia Molecular (ICMol), Universitat de València, Paterna 46980, Spain.
ACS Appl Mater Interfaces. 2022 Jul 15;14(29):33482-90. doi: 10.1021/acsami.2c05464.
Single-layer semiconducting transition metal dichalcogenides (2H-TMDs) display robust excitonic photoluminescence emission, which can be improved by controlled changes to the environment and the chemical potential of the material. However, a drastic emission quench has been generally observed when TMDs are stacked in van der Waals heterostructures, which often favor the nonradiative recombination of photocarriers. Herein, we achieve an enhancement of the photoluminescence of single-layer MoS on top of van der Waals FePS. The optimal energy band alignment of this heterostructure preserves light emission of MoS against nonradiative interlayer recombination processes and favors the charge transfer from MoS, an n-type semiconductor, to FePS, a p-type narrow-gap semiconductor. The strong depletion of carriers in the MoS layer is evidenced by a dramatic increase in the spectral weight of neutral excitons, which is strongly modulated by the thickness of the FePS underneath, leading to the increase of photoluminescence intensity. The present results demonstrate the potential for the rational design of van der Waals heterostructures with advanced optoelectronic properties.
单层半导体过渡金属二硫属化物（2H-TMDs）表现出强烈的激子光致发光发射，通过对材料的环境和化学势进行可控改变可以增强这种发射。然而，当TMDs堆叠在范德华异质结构中时，通常会观察到强烈的发射猝灭，这往往有利于光载流子的非辐射复合。在此，我们实现了在范德华FePS顶部的单层MoS光致发光的增强。这种异质结构的最佳能带排列能够保护MoS的发光免受非辐射层间复合过程的影响，并有利于电荷从n型半导体MoS转移到p型窄带隙半导体FePS。中性激子光谱权重的显著增加证明了MoS层中载流子的强烈耗尽，而这受到下方FePS厚度的强烈调制，导致光致发光强度增加。目前的结果证明了合理设计具有先进光电特性的范德华异质结构的潜力。
