Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
Sci Rep. 2017 Apr 5;7:46004. doi: 10.1038/srep46004.
Remarkable optical properties, such as quantum light emission and large optical nonlinearity, have been observed in peculiar local sites of transition metal dichalcogenide monolayers, and the ability to tune such properties is of great importance for their optoelectronic applications. For that purpose, it is crucial to elucidate and tune their local optical properties simultaneously. Here, we develop an electric field-assisted near-field technique. Using this technique we can clarify and tune the local optical properties simultaneously with a spatial resolution of approximately 100 nm due to the electric field from the cantilever. The photoluminescence at local sites in molybdenum-disulfide (MoS) monolayers is reversibly modulated, and the inhomogeneity of the charge neutral points and quantum yields is suggested. We successfully etch MoS crystals and fabricate nanoribbons using near-field techniques in combination with an electric field. This study creates a way to tune the local optical properties and to freely design the structural shapes of atomic monolayers using near-field optics.
在过渡金属二卤化物单层的特殊局域位置观察到了显著的光学性质，如量子发光和大的光学非线性，并且能够调节这些性质对于它们的光电应用非常重要。为此，阐明和同时调节它们的局域光学性质是至关重要的。在这里，我们开发了一种电场辅助的近场技术。使用这种技术，由于悬臂梁的电场，我们可以以大约 100nm 的空间分辨率同时阐明和调节局域光学性质。在二硫化钼 (MoS) 单层中的局部位置的光致发光可以被可逆地调制，并且表明了电荷中性点和量子产率的非均匀性。我们成功地使用近场技术结合电场刻蚀了 MoS 晶体并制造了纳米带。这项研究为使用近场光学来调节局部光学性质和自由设计原子单层的结构形状创造了一种方法。
