Monolayer transition metal dichalcogenides have recently attracted great interests because the quantum dots embedded in monolayer can serve as optically active single-photon emitters. Here, we provide an interpretation of the recombination mechanisms of these quantum emitters through polarization-resolved and magneto-optical spectroscopy at low temperature. Three types of defect-related quantum emitters in monolayer tungsten diselenide (WSe₂) are observed, with different exciton g-factors of 2.02, 9.36, and unobservable Zeeman shift, respectively. The various magnetic response of the spatially localized excitons strongly indicate that the radiative recombination stems from the different transitions between defect-induced energy levels, valance, and conduction bands. Furthermore, the different g-factors and zero-field splittings of the three types of emitters strongly show that quantum dots embedded in monolayer have various types of confining potentials for localized excitons, resulting in electron–hole exchange interaction with a range of values in the presence of anisotropy. Our work further sheds light on the recombination mechanisms of defect-related quantum emitters and paves a way toward understanding the role of defects in single-photon emitters in atomically thin semiconductors.

单层过渡金属二卤化物最近引起了极大的兴趣，因为嵌入单层的量子点可以用作光学活性的单光子发射器。在这里，我们通过在低温下的偏振分辨和磁光光谱学来解释这些量子发射体的复合机理。单层二硒化钨（WSe _2）中三种与缺陷相关的量子发射体观察到），分别具有2.02、9.36和不可观察的塞曼位移的不同激子g因子。空间局部激子的各种磁响应强烈表明，辐射重组是由缺陷诱导的能级，价态和导带之间的不同过渡引起的。此外，三种发射体的不同g因子和零场分裂强烈表明，嵌入单分子层的量子点对局域激子具有各种类型的约束势能，从而导致电子-空穴交换相互作用并具有一定范围内的值。各向异性的存在。