In this work, the doping effects of rare-earth La and Ce atoms on electronic and optical properties of Janus MoSSe monolayer are investigated by means of first principles calculations. Our results imply that when one La and Ce doped to one S or Se side of Janus MoSSe monoalayer, it leads to a decrease in the band gap and results in the transition from direct to indirect. With increasing the La and Ce doping concentration, the Janus MoSSe monolayer switched from semiconductor to metal. Moreover, we find that effective masses of all the La and Ce doped Janus MoSSe systems are decreased as compared to pristine state, rendering their high carrier mobility. Furthermore, all the La and Ce doped MoSSe systems have red shift and possess high absorption ability in the visible and infrared regions. These findings suggest that rare-earth La and Ce doped MoSSe monolayer are potential candidate for spintronics, nanoelectronics and optoelectronics.

在这项工作中，通过第一性原理计算研究了稀土La和Ce原子对Janus MoSSe单层电子和光学性质的掺杂效应。我们的结果表明，当一个La和Ce掺杂到Janus MoSSe单层膜的一侧S或Se时，会导致带隙减小，并导致从直接过渡到间接。随着La和Ce掺杂浓度的增加，Janus MoSSe单层从半导体转变为金属。此外，我们发现，与原始状态相比，所有La和Ce掺杂的Janus MoSSe系统的有效质量都降低了，从而使其具有较高的载流子迁移率。此外，所有La和Ce掺杂的MoSSe系统都具有红移，并在可见光和红外区具有高吸收能力。