Mi Yang, Zhang Zhepeng, Zhao Liyun, Zhang Shuai, Chen Jie, Ji Qingqing, Shi Jianping, Zhou Xiebo, Wang Rui, Shi Jia, Du Wenna, Wu Zhiyong, Qiu Xiaohui, Zhang Qing, Zhang Yanfeng, Liu Xinfeng
Division of Nanophotonics, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China.
Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, P. R. China.
Small. 2017 Nov;13(42). doi: 10.1002/smll.201701694. Epub 2017 Sep 20.
Tuning the optical properties of 2D direct bandgap semiconductors is crucial for applications in photonic light source, optical communication, and sensing. In this work, the excitonic properties of molybdenum disulphide (MoS ) are successfully tuned by directly depositing it onto silica microsphere resonators using chemical vapor deposition method. Multiple whispering gallery mode (WGM) peaks in the emission wavelength range of ≈650-750 nm are observed under continuous wave excitation at room temperature. Time-resolved photoluminescence (TRPL) and femtosecond transient absorption (TA) spectroscopy are conducted to study light-matter interaction dynamics of the MoS microcavities. TRPL study suggests radiative recombination rate of carrier-phonon scattering and interband transition processes in MoS is enhanced by a factor of ≈1.65 due to Purcell effect in microcavities. TA spectroscopy study shows modulation of the interband transition process mainly occurs at PB-A band with an estimated F ≈ 1.60. Furthermore, refractive index sensing utilizing WGM peaks of MoS is established with sensitivity up to ≈150 nm per refractive index unit. The present work provides a large-scale and straightforward method for coupling atomically thin 2D gain media with cavities for high-performance optoelectronic devices and sensors.
调节二维直接带隙半导体的光学性质对于其在光子光源、光通信和传感等领域的应用至关重要。在这项工作中，通过化学气相沉积法将二硫化钼（MoS₂）直接沉积到二氧化硅微球谐振器上，成功地调节了其激子特性。在室温下连续波激发下，观察到在≈650 - 750 nm发射波长范围内的多个回音壁模式（WGM）峰。进行了时间分辨光致发光（TRPL）和飞秒瞬态吸收（TA）光谱研究，以研究MoS₂微腔的光与物质相互作用动力学。TRPL研究表明，由于微腔中的珀塞尔效应，MoS₂中载流子 - 声子散射和带间跃迁过程的辐射复合率提高了约1.65倍。TA光谱研究表明，带间跃迁过程的调制主要发生在PB - A带，估计调制因子F≈1.60。此外，利用MoS₂的WGM峰建立了折射率传感，灵敏度高达≈150 nm/折射率单位。本工作为将原子级薄的二维增益介质与腔体耦合以用于高性能光电器件和传感器提供了一种大规模且直接的方法。
