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arXiv 1405.4334cond-mat.mtrl-sci
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通过缺陷工程和氧键合增强MoS2的强光致发光

Strong Photoluminescence Enhancement of MoS2 through Defect Engineering and Oxygen Bonding

Haiyan Nan, Zilu Wang, Wenhui Wang, Zheng Liang, Yan Lu, Qian Chen, Daowei He, Pingheng Tan, Feng Miao, Xinran Wang, Jinlan Wang, Zhenhua Ni

摘要:

我们报告了一个强大的光致发光(PL)增强单层二硫化钼通过缺陷工程和氧键合。显微光致发光和拉曼图像清楚地揭示了在高温真空退火过程中形成的裂纹/缺陷处发生的光致发光增强。在考虑激光光斑尺寸后,裂纹/缺陷位置处的PL增强可以高达数千倍。这种巨大的PL增强的主要原因包括:(1)氧化学吸附导致的重p掺杂和从三电子到激子的转换;(2)低温PL测量证实的缺陷位置处激子的非辐射复合的抑制。第一性原理计算揭示了一个强大的结合能为2.395 eV的氧分子吸附在一个S空位的二硫化钼。化学吸附的氧还提供了一个更有效的电荷转移(0.997电子每O2)相比,物理吸附的氧在理想的二硫化钼表面。我们还表明,缺陷工程和氧键合可以很容易地实现氧等离子体辐照。X射线光电子能谱学进一步证实了Mo-O键的形成。我们的结果为二维半导体的光学性质的调制提供了一条新的途径。MoS 2缺陷位产生的强而稳定的光致发光在光电子器件中具有广阔的应用前景。

英文摘要:

We report on a strong photoluminescence (PL) enhancement of monolayer MoS2 through defect engineering and oxygen bonding. Micro- PL and Raman images clearly reveal that the PL enhancement occurs at cracks/defects formed during high temperature vacuum annealing. The PL enhancement at crack/defect sites could be as high as thousands of times after considering the laser spot size. The main reasons of such huge PL enhancement include: (1) the oxygen chemical adsorption induced heavy p doping and the conversion from trion to exciton; (2) the suppression of non-radiative recombination of excitons at defect sites as verified by low temperature PL measurements. First principle calculations reveal a strong binding energy of ~2.395 eV for oxygen molecule adsorbed on an S vacancy of MoS2. The chemical adsorbed oxygen also provides a much more effective charge transfer (0.997 electrons per O2) compared to physical adsorbed oxygen on ideal MoS2 surface. We also demonstrate that the defect engineering and oxygen bonding could be easily realized by oxygen plasma irradiation. X-ray photoelectron spectroscopy further confirms the formation of Mo-O bonding. Our results provide a new route for modulating the optical properties of two dimensional semiconductors. The strong and stable PL from defects sites of MoS2 may have promising applications in optoelectronic devices.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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