Monash Centre for Atomically Thin Materials, Monash University , Victoria 3800, Australia.
Nano Lett. 2016 Feb 10;16(2):849-55. doi: 10.1021/acs.nanolett.5b02826. Epub 2016 Jan 7.
By exploiting the very recent discovery of the piezoelectricity in odd-numbered layers of two-dimensional molybdenum disulfide (MoS2), we show the possibility of reversibly tuning the photoluminescence of single and odd-numbered multilayered MoS2 using high frequency sound wave coupling. We observe a strong quenching in the photoluminescence associated with the dissociation and spatial separation of electrons-holes quasi-particles at low applied acoustic powers. At the same applied powers, we note a relative preference for ionization of trions into excitons. This work also constitutes the first visual presentation of the surface displacement in one-layered MoS2 using laser Doppler vibrometry. Such observations are associated with the acoustically generated electric field arising from the piezoelectric nature of MoS2 for odd-numbered layers. At larger applied powers, the thermal effect dominates the behavior of the two-dimensional flakes. Altogether, the work reveals several key fundamentals governing acousto-optic properties of odd-layered MoS2 that can be implemented in future optical and electronic systems.
利用最近发现的二维二硫化钼（MoS2）奇数层的压电性，我们展示了使用高频声波耦合来可逆地调节单层和奇数层 MoS2 的光致发光的可能性。我们观察到在低施加声功率下，与电子空穴准粒子的离解和空间分离相关的光致发光的强烈猝灭。在相同的施加功率下，我们注意到三离子向激子的电离有相对偏好。这项工作还首次使用激光多普勒测振仪展示了单层 MoS2 的表面位移。这种观察与由 MoS2 的压电性质产生的声致电场相关，对于奇数层而言。在更大的施加功率下，热效应主导了二维薄片的行为。总的来说，这项工作揭示了控制奇数层 MoS2 的声光特性的几个关键基础，这些特性可在未来的光学和电子系统中实现。
