Blundo Elena, Tuzi Federico, Cuccu Marzia, Re Fiorentin Michele, Pettinari Giorgio, Patra Atanu, Cianci Salvatore, Kudrynskyi Zakhar R, Felici Marco, Taniguchi Takashi, Watanabe Kenji, Patanè Amalia, Palummo Maurizia, Polimeni Antonio
Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
Nano Lett. 2025 Mar 5;25(9):3375-3382. doi: 10.1021/acs.nanolett.4c04252. Epub 2025 Feb 5.
Two-dimensional (2D) heterostructures (HSs) offer unlimited possibilities for playing with layer number, order, and twist angle. The realization of high-performance optoelectronic devices, however, requires the achievement of specific band alignments, -space matching between conduction and valence band extrema, and efficient charge transfer between the constituent layers. Fine-tuning mechanisms to design ideal HSs are lacking. Here, we show that layer-selective strain engineering can be exploited as an extra degree of freedom to tailor the band alignment and optical properties of 2D HSs. To that end, strain is selectively applied to MS (M = Mo or W) monolayers in InSe/MS HSs, triggering a giant photoluminescence enhancement of the highly tunable but weakly emitting InSe of up to >2 orders of magnitude. Resonant excitation measurements, supported by first-principles calculations, provide evidence of a strain-activated charge transfer from the MS monolayers toward InSe. The huge emission enhancement of InSe widens its range of applications for optoelectronics.
二维（2D）异质结构为调控层数、顺序和扭转角提供了无限可能。然而，高性能光电器件的实现需要特定的能带排列、导带和价带极值之间的 - 空间匹配以及组成层之间有效的电荷转移。目前缺乏用于设计理想异质结构的微调机制。在此，我们表明层选择性应变工程可作为一种额外的自由度来调控二维异质结构的能带排列和光学性质。为此，在InSe/MS异质结构中，应变被选择性地施加到MS（M = Mo或W）单层上，引发了高度可调但发光较弱的InSe的光致发光增强高达2个数量级以上。在第一性原理计算的支持下，共振激发测量提供了应变激活电荷从MS单层向InSe转移的证据。InSe的巨大发射增强拓宽了其在光电子学中的应用范围。
