直立生长的SnS_(2)薄膜的三阶非线性光学性质研究(特邀)  

Third-order Nonlinear Optical Properties of Vertically Aligned SnS_(2)Films(Invited)

作　　者：葛燕青 刘玉琪 卢春辉 罗铭威 韩涛涛 周译玄 徐新龙 GE Yanqing;LIU Yuqi;LU Chunhui;LUO Mingwei;HAN Taotao;ZHOU Yixuan;XU Xinlong(Institute of Photonics&Photon-technology,School of Physics,Northwest University,Xi′an 710127,China)

机构地区：[1]西北大学物理学院光子学与光子技术研究所,西安710127

出　　处：《光子学报》2022年第10期290-297,共8页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.12074311,11974279)。

摘　　要：采用化学气相沉积法制备了直立生长的SnS_(2)(V-SnS_(2))薄膜,并使用自主搭建的Z扫描系统研究了V-SnS_(2)的三阶非线性光学响应。结果表明,由于S空位的存在使得V-SnS_(2)薄膜表现出明显的饱和吸收响应,且非线性吸收系数(β)随着泵浦功率的增加而减少。分析发现,其β的最大值为6 cm/GW,调制深度(ΔM)为50%。同时,通过闭口Z扫描技术测量发现V-SnS_(2)薄膜的n_(2)比Si和GaAs大一个数量级,且n_(2)随着泵浦功率的增加而减少,基于自由载流子的非线性理论分析表明这与材料中的自由载流子和束缚电子密切相关。本文研究证明V-SnS_(2)在全光开关、激光调Q等非线性光电子器件的设计与制造方面有潜在的应用。Two-dimensional(2D)layered metal dichalcogenides have attracted extensive attention due to their unique physicochemical properties,such as high carrier mobility,strong light-matter interaction and tunable band gap.Tin disulfide(SnS_(2)),as an emerging 2D layered metal dichalcogenides with a narrow band gap(2.0~2.6 eV),has a CDI_(2)type crystal structure and the layered structure is formed by a stack of sandwiched S-Sn-S planes connected by van der Waals force.Furthermore,SnS_(2)is non-toxic,low-cost,and storage abundant,which meets the need of industrial production of electronic and optoelectronic devices.It also exhibits excellent photoelectric responses such as high absorption coefficient(α_(0)~10^(5)~10^(6)cm^(-1)),large on/off ratio(>10^(6)),high carrier mobility(230 cm^(2)V^(-1)S^(-1)),and so on,which ensures its rapid development in photoelectric applications such as photodetectors,solar cells and photocatalysis.However,so far,research on the nonlinear optical properties of SnS_(2)films is still in infancy.In the early stage,SnS_(2)was prepared by liquid phase exfoliation technique to firstly explore its nonlinear optical properties.The SnS_(2)films always show saturable absorption under the lower photon energy than band gap.This saturable absorption can be explained by some surface defects,coming from the growth process.As such,many novel 2D semiconductors such as WS_(2)and MoS_(2)with S vacancy defect also have been demonstrated and successfully applied into mode-locked,Q-switched,and other photonic devices.The defects can capture excitons,electrons,and holes to modulate nonlinear absorption.Thus,it is necessary to confirm the defect type and then systematically analyze the nonlinear optical response of SnS_(2)films.Compared with horizontally aligned 2D film,vertically aligned materials have larger specific surface area and exposed edge sites,thus resulting in higher light absorption characteristics.Furthermore,the active edges of MoS_(2)have shown a strong resonant nonlinear optical susceptibility and t

关 键 词：SnS_(2) 非线性吸收 非线性折射 泵浦功率依赖 Z扫描 

分 类 号：O437[机械工程—光学工程]