Rahman Sharidya, Liu Boqing, Wang Bowen, Tang Yilin, Lu Yuerui
Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra 2601, Australia.
ACS Appl Mater Interfaces. 2021 Feb 17;13(6):7423-7433. doi: 10.1021/acsami.0c20110. Epub 2021 Feb 3.
Hybridization of two-dimensional (2D) magnetic semiconductors with transition-metal dichalcogenides (TMDC) monolayers can significantly engineer the light-matter interactions and provide a promising platform for enhanced excitonic systems with artificially tailored band alignments. Here, we report the fabrication of heterostructures with monolayer WS on 2D CrGeTe (CGT), which displayed giant photoluminescence enhancement at specific CGT layer numbers. The highly enhanced quantum yield obtained can be explained by novel photoexcited carrier dynamics, facilitated by alternate relaxation channels, resulting in resonance charge transfer at the heterointerface. 2D CGT revealed a strongly layer-dependent work function (up to ∼750 meV), which greatly modulates the band positioning in the heterostructure. These heterostructures conceived both type I and type II band alignments, which are verified by Kelvin probe force microscopy and PL measurements. In addition to layer modulation, we uncover temperature and power dependence of the resonance charge transfer in the multilayer heterostructure. Our findings provide further insights into the ultrafast charge dynamics occurring at the atomic interfaces. The results may pave the way for novel optoelectronics based on van der Waals heterostructures.
二维（2D）磁性半导体与过渡金属二硫属化物（TMDC）单层的杂交可以显著地调控光与物质的相互作用，并为具有人工定制能带排列的增强激子系统提供一个有前景的平台。在此，我们报告了在二维CrGeTe（CGT）上制备具有单层WS的异质结构，该异质结构在特定的CGT层数下表现出巨大的光致发光增强。所获得的高度增强的量子产率可以通过新颖的光激发载流子动力学来解释，这种动力学由交替的弛豫通道促进，导致在异质界面处的共振电荷转移。二维CGT显示出强烈的层依赖功函数（高达约750毫电子伏特），这极大地调节了异质结构中的能带定位。这些异质结构呈现出I型和II型能带排列，这通过开尔文探针力显微镜和PL测量得到了验证。除了层调制之外，我们还揭示了多层异质结构中共振电荷转移的温度和功率依赖性。我们的发现为原子界面处发生的超快电荷动力学提供了进一步的见解。这些结果可能为基于范德华异质结构的新型光电器件铺平道路。
