题目：Momentum-Direct Infrared Interlayer Exciton and Photodetection in Multilayer van der Waals Heterostructures
作者：Chao Zhang1,2, Kai Wu1,2, Lu Gan3, Xiaoyi Liu1,2, Cheng Zhang1,2, Shaolong Wu1,2, Xiaoming Yuan4, Linglong Zhang5,6, Jinyang Xi3,7*, Jiong Yang1,2*, Xiaofeng Li1,2*
单位：
1School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
2Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006, China.
3Materials Genome Institute, Shanghai University, Shanghai 200444, China.
4Hunan Key Laboratory of Super Microstructure and Ultrafast Process, School of Physics, Central South University, Changsha, Hunan 410083, China
5College of Physics, Nanjing University of Aeronautics and Astronautics, Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing 211106, China.
6Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
7Zhejiang Laboratory, Hangzhou, Zhejiang 311100, China.
摘要：Interlayer excitons (IX), spatially separated electron–hole pair quasiparticles, can form in type-II van der Waals heterostructures (vdWH). To date, the most widely studied IX in hetero- and homobilayer transition metal dichalcogenides feature momentum-indirect and visible interlayer recombinations. However, momentum-direct IX emissions and interlayer absorptions, especially in the infrared, are crucial for excitonic devices but remain underexplored. In this work, we propose and construct a multilayer WSe2/InSe vdWH that hosts momentum-direct IX and manifests near-infrared interlayer absorptions at room temperature, verified by first-principles density functional theory calculations. We conduct power- and temperature-dependent photoluminescence spectroscopies and extract the IX binding energy to be 43 ± 5 meV. Furthermore, we manipulate the IX emission electrically via the Stark effect and tune its energy by 180 meV. Taking advantage of the direct interlayer absorption, we fabricate a near-infrared vdWH photodetector modulated by strong photogating effect, and achieve the optimal photoresponsivity, specific detectivity, and response time of 33 A W–1, 1.8 × 1010 Jones, and 3.7 μs at 1150 nm. In addition, we test the imaging capability of the photodetector by integrating it into a single-pixel imaging system. Our work showcases the possibility for constructing infrared-responsive vdWH that hosts momentum-direct IX for future excitonic devices of optoelectronic applications.
二维材料异质结或同质结中的层间激子可应用于基础物理的研究和新型光电子器件的制备。目前，红外波段的直接带隙层间激子和层间吸收报道较少。苏州大学光电学院的杨炯教授和李孝峰教授团队制备出多层WSe2/InSe异质结，观测到其在1130纳米处的直接带隙层间激子发光。DFT计算表明该异质结价带顶和导带底均位于布里渊区中心的Gamma点，具有高度对称性，其层间跃迁不受扭转角的影响。通过光学、电学和温度调控，我们发现该层间激子结合能为43 ± 5毫电子伏特，可在室温下稳定存在。利用异质结中的红外层间吸收以及光致栅（photogating）效应，我们制备出高性能快速响应的红外光电探测器；在1150纳米处，响应度和响应时间分别为33安培/瓦以及3.7微秒。该研究为基于二维异质结的红外激子和光电子器件提供了一种新的解决方案。
影响因子：15.8
链接：//pubs.acs.org/doi/10.1021/acsnano.4c11195