Preparation of Few quintuple layers Bismuth selenide (Bi₂Se₃) by spin coated-coreduction approach (SCCA) and Optical nonlinearity was discussed

Topological insulators (TIs) have been realized their functionality of saturation absorption (SA) for pulsing lasers. Recently, using spin coated-coreduction approach (SCCA) growth Bi₂Te₃ thin film, continuous wave mode locking (CWML) solid state laser with repetition rate as high as GHz has been demonstrated. Compared to Bi₂Te₃, Bi₂Se₃ has been theoretically and experimentally investigated with p-type nature, leading to greater potential to be a SA. However, the difficulty of preparing high optical thin film results in the less report about their application for pulsed lasers. In this study, large area topological insulator thin film Bi₂Se₃ (Bismuth Selenide) of few quintuple layers were prepared by spin coated-coreduction approach (SCCA). AFM image, TEM image, XPS, XRD, Raman pattern all show that the growth Bi₂Se₃ thin film is with high crystalline quality. In addition, the application of Bi₂Se₃ for pulsing solid state laser was studied and discussed as well.