【作者】 李平；

【导师】 游陆；

【作者基本信息】 苏州大学 ， 物理学， 2022， 硕士

【摘要】 二维范德华材料的自支撑特性为构建多功能的范德华异质结提供了很大的自由度,其中将二维半导体材料和铁电材料组合而成的非易失性场效应异质结是低功耗功能器件研究的重要方向之一。铁电材料在居里温度以下具有可翻转的极化特征常被当做调控半导体内载流子的开关,并且这种非易失性的极化与力、热、电和光之间的协同耦合作用极大的拓展了器件的功能性。伴随着二维范德华铁电的出现,基于纯二维范德铁电异质结的多功能电子器件原型在近年来大量涌现。然而绝大多数工作更注重于器件的应用概念和工作性能,对其内在的界面耦合物理机制的研究较少。有鉴于此,我们以二维范德华铁电异质结MoS2/CuInP2S6(CIPS)为研究对象,借助压电力、开尔文探针、拉曼和荧光光谱等多种显微成像表征手段,对铁电极化如何调控MoS2的光电性质展开了深入的系统研究,阐明了极化电荷、注入电荷和载流子电荷在异质界面处的静电耦合微观机制,证实了范德华异质结中注入电荷对于调控二维半导体材料的光电特性的重要作用。此外,通过对非铁电范德华异质结的研究,表明了注入电荷效应在范德华异质结中的普适性,这对基于范德华异质结的电子、光电器件的研究具有广泛的启示作用。更多还原

【Abstract】 The freestanding nature of two-dimensional(2D)van der Waals(vdW)materials provides large degrees of freedom for constructing multi-functional vdW heterostructures,among which the integration of two-dimensional semiconducting materials with ferroelectric materials as nonvolatile field-effect devices are becoming one of the current mainstream directions.Ferroelectric materials have reversible polarization below the Curie temperature and are often used as switches for regulating charge carriers in semiconductors,and the synergy effect between non-volatile polarization and strain,temperature,electric field,and light greatly expand the functionalities of the devices.With the emergence of 2D vdW ferroelectrics,various electronic device paradigms have burgeoned in recent years.However,most of the work focused more on the application concepts and their device performances,instead of the inherent coupling physics at the heterointerfaces.In view of this,the 2D vdW ferroelectric heterostucture MoS2/CuInP2S6(CIPS)have built in this thesis,and carried out a systematic study of the polarization switching effect on the optoelectronic properties of MoS2 with the help of various microscopic characterization techniques,such as piezoresponse force microscopy,scanning Kelvin probe microscopy,Raman and photoluminescence spectroscopies,etc.We elucidated the microscopic electrostatic coupling mechanims of polarization charges,injected charges and carrier charges at the heterointerface,and confirmed the dominant role of injected charges in the modulating the optoelectronic properties of 2D semiconductor materials in the vdW heterojunction.Besides,by investigating into the non-ferroelectric vdW heterostructure,the universality of the injected charge effect in vdW heterojunctions is demonstrated,which has broad implications for future research on vdW heterojunction-based electronic and optoelectronic devices.更多还原