MoS_(2)/Bi_(2)Se_(3)异质结的制备及其光致发光性能研究

Preparation and photoluminescence performance of MoS_(2)/Bi_(2)Se_(3)heterostructures

二硫化钼(MoS_(2))是一种典型的二维材料,因其具备高电子迁移率、可调的带隙和高光吸收度等优异性能被广泛应用于光电子领域.二维硒化铋(Bi_(2)Se_(3))拥有随层数变化的特殊表面态.单层MoS_(2)和多层及少层Bi_(2)Se_(3)薄膜构筑成异质结构时,其光致发光性质可能发生显著改变.该文利用气相沉积法成功制备了单层MoS_(2)单晶和5层及较厚的Bi_(2)Se_(3)薄膜,并通过转移法成功构筑了基于5层及较厚的Bi_(2)Se_(3)薄膜的MoS_(2)/Bi_(2)Se_(3)垂直异质结.在此基础上,结合拉曼、光致发光(PL)测试技术,对两种异质结中的激子发光、界面间相互作用和电荷转移进行了研究,发现基于5层Bi_(2)Se_(3)的MoS_(2)/Bi_(2)Se_(3)异质结具有PL显著增强现象,而基于较厚的Bi_(2)Se_(3)的MoS_(2)/Bi_(2)Se_(3)异质结的PL却明显减弱.研究结果表明二维Bi_(2)Se_(3)随层数可变的表面态对MoS_(2)的光学性能具有显著的调制效应.

Molybdenum disulfide(MoS_(2))is a typical two-dimensional material,which has been widely used in the field of optoelectronics because of its excellent properties such as high electron mobility,adjustable band gap and high light absorption.Two-dimensional bismuth selenide(Bi_(2)Se_(3))can generate a“finite size effect”at 5 and less layers.The photoluminescence(PL)properties of Bi_(2)Se_(3)films may change significantly when monolayer MoS_(2)and few layers Bi_(2)Se_(3)films are constructed as a heterostructure.In this paper,monolayer MoS_(2)crystal and Bi_(2)Se_(3)films with 5 or more layers were successfully prepared by vapor deposition method.Subsequently,we created vertical heterostructures of MoS_(2)/Bi_(2)Se_(3)through a solution transfer method.The exciton behavior,interfacial interaction and charge transfer in MoS_(2)/Bi_(2)Se_(3)heterostructures were systematically studied by combining Raman and fluorescence spectroscopy techniques.The experimental results indicated that the PL performance of the heterostructure experiences a remarkable enhancement for the Bi_(2)Se_(3)film with 5 layers but is significantly weakened for Bi_(2)Se_(3)films thicker than 5 layers.The experimental results show that the surface states of Bi_(2)Se_(3)can regulate optical properties of MoS_(2)effectively.