二维半导体硒化钨的多相可控生长和二次谐波增强  

Multiphase Controllable Growth and Second Harmonic Enhancement ofTwo-Dimensional Semiconductor WSe_(2)

作　　者：王广[1] 姚博文 吕志权 Wang Guang;Yao Bowen;LüZhiquan(College of Science,National University of Defense Technology,Changsha 410073,Hunan,China)

机构地区：[1]国防科技大学理学院,湖南长沙410073

出　　处：《光学学报》2024年第4期227-236,共10页Acta Optica Sinica

基　　金：湖南省杰出青年科学基金(2022JJ10060)。

摘　　要：采用化学气相沉积方法和逆向气流策略,成功地可控合成了均匀、平整、结晶良好的单层、2H相、3R相以及螺旋结构硒化钨(WSe_(2))单晶,利用光学显微镜、原子力显微镜、拉曼和光致发光光谱等表征进行测试分析,证实了WSe_(2)具有优异的晶体质量。通过精确控制炉腔温度分布实现了不同原子层堆垛方式的生长调控,利用过饱和度理论分析推测出螺旋堆垛及位错臂的数量与不同过饱和度分布之间的关系,在螺旋的WSe_(2)结构中观测到了两个数量级的二次谐波产生(SHG)增强,通过SHG偏振特性表征螺旋结构的偏转角度,揭示了层间耦合作用和内部应变对螺旋堆垛的影响,有助于推动二维半导体多相可控生长和光电物性调控研究。Objective In recent years,there have been many studies on the preparation of high-quality transition-metal dichalcogenides(TMDCs),which have a variety of applications including optoelectronics,spin-tronics,and valleytronics.The most attractive properties of TMDCs as candidates for such diverse applications are layer and phase dependence.Therefore,the controlled growth of various phases of TMDCs and the stacking of distinct layers have emerged as popular research realms.In previous research,people have summarized the theory of supersaturation-dependent crystal growth by continuously refining the classical BCF(Burton-Cabrera-Frank)theory.However,on the one hand,supersaturationdependent growth theory is often employed to provide a theoretical interpretation for preparing a certain phase that lacks systematicity,and on the other hand,the parameter control involved in such theories is difficult to measure and regulate experimentally.Our study focuses on controlling the temperature distribution to affect the supersaturation degree and achieve the one-step controllable growth of three phases of WSe_(2)(single layer,3R,and 2H)directly on the different regions at the substrate under a temperature gradient.By regulating the temperature distribution,we can change the supersaturation distribution and successfully prepare spiral plates of WSe_(2) by screw-dislocation-driven(SDD)growth mode,transitioning from layer-by-layer(LBL)growth mode,where we observe two orders of magnitude of second harmonic generation(SHG)signal enhancement in the spiral-stacked region.These different vertically stacked TMDCs materials will offer diverse candidates for probing the physical properties of layered materials and exploring new applications in functional electronic and optoelectronic devices.Methods Our experiments adopt the reverse flow method to control the growth time and growth temperature in the growth process and shorten the cooling time by a rapid cooling method.With the help of the supersaturation-dependent crystal growth theory and

关 键 词：材料 过渡金属硫族化合物 逆向气流化学气相沉积 螺旋堆垛 二次谐波产生 

分 类 号：O436[机械工程—光学工程]