Ye Kun, Yan Junxin, Li Qian, Wang Linyan, Gao Yang, Wang Liming, Zhang Fang, Jia Zhiyan, Liu Lixuan, Nie Anmin, Wang Shouguo, Jiang Yong, Liu Zhongyuan
School of Electronics and Information Engineering, Institute of Quantum Materials and Devices, State Key Laboratory of Separation Membrane and Membrane Processes, Tiangong University, Tianjin 300387, China.
Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China.
ACS Nano. 2025 Jan 14;19(1):1340-1351. doi: 10.1021/acsnano.4c13870. Epub 2025 Jan 2.
Moiré superlattices, created by stacking different van der Waals materials at twist angles, have emerged as a versatile platform for exploring intriguing phenomena such as topological properties, superconductivity, the quantum anomalous Hall effect, and the unconventional Stark effect. Additionally, the formation of moiré superlattice potential can generate spontaneous symmetry breaking, leading to an anisotropic optical response and electronic transport behavior. Herein, we propose a two-step chemical vapor deposition (CVD) strategy for synthesizing WS/SbS moiré superlattices. Density functional theory calculations show that the moiré potential and interlayer distance at the WS/SbS interface can generate anisotropic electronic states. The atomic-resolution HAADF-STEM image clearly reveals angle-dependent complicated moiré periodicity. The polarization-dependent second harmonic generation, Raman, photoluminescence, and absorption spectroscopy of the WS/SbS heterostructure confirm optical anisotropic behavior due to symmetry breaking by the moiré superlattice formation. The WS/SbS device exhibits high on/off ratios up to 10, a relatively low leakage current of 10 A, and a broadband optoelectronic response range from 360 to 914 nm. Notably, the broken symmetry by -symmetric SbS nanowires grown on a -symmetric WS nanosheet endows the WS/SbS photodetector with strong polarization-dependent photocurrent intensity and high-resolution polarization imaging capability. Our study demonstrates the potential for constructing multifunctional moiré materials by incorporating symmetry-breaking engineering.
通过以扭转角堆叠不同的范德华材料而创建的莫尔超晶格，已成为探索诸如拓扑性质、超导性、量子反常霍尔效应和非常规斯塔克效应等有趣现象的通用平台。此外，莫尔超晶格势的形成可以产生自发对称性破缺，导致各向异性的光学响应和电子输运行为。在此，我们提出了一种两步化学气相沉积（CVD）策略来合成WS/SbS莫尔超晶格。密度泛函理论计算表明，WS/SbS界面处的莫尔势和层间距离可以产生各向异性的电子态。原子分辨率的高角度环形暗场扫描透射电子显微镜（HAADF-STEM）图像清楚地揭示了与角度相关的复杂莫尔周期性。WS/SbS异质结构的偏振相关二次谐波产生、拉曼光谱、光致发光和吸收光谱证实了由于莫尔超晶格形成导致的对称性破缺而产生的光学各向异性行为。WS/SbS器件表现出高达10的开/关比、相对较低的10 A泄漏电流以及360至914 nm的宽带光电响应范围。值得注意的是，在对称的WS纳米片上生长的对称SbS纳米线的对称性破缺赋予了WS/SbS光电探测器强烈的偏振相关光电流强度和高分辨率偏振成像能力。我们的研究证明了通过纳入对称性破缺工程来构建多功能莫尔材料的潜力。
