亚波长介质光栅对单层过渡金属硫化物的发光增强

Enhancement of photoluminescence of monolayer transition metal dichalcogenide by subwavelength TiO_(2) grating

过渡金属硫化物单层具有直接带隙,可产生较强的光致发光,这一特殊的性质使其在光电器件、光电探测等领域具有广泛的应用前景.由于只有原子级别的厚度以及存在激子的非辐射复合,其光致发光效率仍有待提高.本文设计了一种金膜-二氧化钛光栅-过渡金属硫化物单层组合结构,可大幅提升过渡金属硫化物单层光致发光效率.利用Purcell效应对自发辐射速率进行控制,得到峰值为3.4倍的发光增强.研究了单层二硫化钨以及单层二硒化钨在设计结构上的光致发光信号,通过实验证实了过渡金属硫化物单层与亚波长光栅耦合结构中光致发光增强的可行性,为二维材料在光电器件中的应用提供了一个新思路.

Transition metal dichalcogenide(TMDC)monolayers have direct band gaps and can produce strong photoluminescence(PL),thereby possessing a wide application prospect in photoelectric devices and photoelectric detection fields.However,their PL efficiency needs further improving because they are of atomic thickness only,besides,they have non-radiative recombination of excitons.In this study,a combination structure of a gold film,titanium dioxide subwavelength gratings and TMDC monolayers is designed,which can greatly improve PL efficiency of the TMDC monolayers.The spontaneous emission rate can be controlled by the Purcell effect,and the maximum enhancement of photoluminescence is as high as 3.4 times.In this paper,the PL signals of monolayer WS;and monolayer WSe;on the designed structure are studied.The feasibility of the enhancement of PL of the TMDC monolayers on the subwavelength grating structure is verified experimentally,which provides a new idea for the application of two-dimensional materials to optoelectronic devices.