Preparation of few-layer bismuth selenide by liquid-phase-exfoliation and its optical absorption properties.
Bismuth selenide (Bi2Se3), a new topological insulator, has attracted much attention in recent years owing to its relatively simple band structure and large bulk band gap. Compared to bulk, few-layer Bi2Se3 is recently considered as a highly promising material. Here, we use a liquid-phase exfoliation method to prepare few-layer Bi2Se3 in N-methyl-2-pyrrolidone or chitosan acetic solution. The resulted few-layer Bi2Se3 dispersion demonstrates an interesting absorption in the visible light region, which is different from bulk Bi2Se3 without any absorption in this region. The absorption spectrum of few-layer Bi2Se3 depends on its size and layer number. At the same time, the nonlinear and saturable absorption of few-layer Bi2Se3 thin film in near infrared is also characterized well and further exploited to generate laser pulses by a passive Q-switching technique. Stable Q-switched operation is achieved with a lower pump threshold of 9.3 mW at 974 nm, pulse energy of 39.8 nJ and a wide range of pulse-repetition-rate from 6.2 to 40.1 kHz. Therefore, the few-layer Bi2Se3 may excite a potential applications in laser photonics and optoelectronic devices.
Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005, China.
Liping
L
Sun
Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005, China.
Zhiqin
Z
Lin
Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005, China.
Jian
J
Peng
1] Department of Biomaterials, College of Materials, Xiamen University, Xiamen 361005, China [2] ShenZhen Research Institute of Xiamen University, Shenzhen 518057, China.
Jian
J
Weng
Institute of Optoelectronic Technology, Department of Electronic Engineering, Xiamen University, Xiamen 361005, China.
Yizhong
Y
Huang
Institute of Optoelectronic Technology, Department of Electronic Engineering, Xiamen University, Xiamen 361005, China.
Zhengqian
Z
Luo