Effects of rhenium dopants on photocarrier dynamics and optical properties of monolayer, few-layer, and bulk MoS2
Effects of rhenium dopants on photocarrier dynamics and optical properties of monolayer, few-layer, and bulk MoS2
复制标题
铼掺杂剂对单层、少层和块状MoS2光载流子动力学和光学性质的影响
作者：
Li Yuanyuan;Liu Qingfeng;Cui Qiannan;Qi Zeming;Wu Judy Z;Zhao Hui
本文报道了铼掺杂对MoS2单层、少层和体样品光学性质和光载流子动力学的影响。采用机械剥离法制备了重掺杂（0.6%）和未掺杂的MoS2单层和少层样品，并通过拉曼光谱、光学吸收、光致发光和时间分辨差分反射测量对其进行了研究。从掺杂和未掺杂样品中获得相似的拉曼光谱、吸收光谱和光致发光光谱，表明该水平的稀土掺杂没有显著改变晶格和电子结构。观察到两个声子拉曼模式的红移和展宽，显示了Re诱导的晶格应变和载流子掺杂。掺杂单层的光致发光产率比未掺杂样品低约15倍，而掺杂单层的光载流子寿命缩短约20倍。这两种观察结果都可以归因于Re掺杂物中光载流子的扩散受限俄歇非辐射复合。这些结果为开发用于光电应用的二硫化钼掺杂策略提供了有用的信息。
We report a comprehensive study on the effects of rhenium doping on optical properties and photocarrier dynamics of MoS2 monolayer, few-layer, and bulk samples. Monolayer and few-layer samples of Re-doped (0.6%) and undoped MoS2 were fabricated by mechanical exfoliation, and were studied by Raman spectroscopy, optical absorption, photoluminescence, and time-resolved differential reflection measurements. Similar Raman, absorption, and photoluminescence spectra were obtained from doped and undoped samples, indicating that the Re doping at this level does not significantly alter the lattice and electronic structures. Red-shift and broadening of the two phonon Raman modes were observed, showing the lattice strain and carrier doping induced by Re. The photoluminescence yield of the doped monolayer is about 15 times lower than that of the undoped sample, while the photocarrier lifetime is about 20 times shorter in the doped monolayer. Both observations can be attributed to diffusion-limited Auger nonradiative recombination of photocarriers at Re dopants. These results provide useful information for developing a doping strategy of MoS2 for optoelectronic applications.