摘要
探索二维材料与其衬底之间的黏附性能对于二维材料的制备、转移以及器件性能的优化至关重要.本文基于原子键弛豫理论和连续介质力学方法,系统研究了尺寸和温度对MoS_(2)/SiO_(2)界面黏附性能的影响.结果表明,由于表面效应引起的热膨胀系数、晶格应变和杨氏模量的变化,MoS_(2)/SiO_(2)界面黏附能随MoS_(2)厚度的减小而增大,而热应变使MoS_(2)/SiO_(2)界面黏附能随温度的升高而逐渐降低.此外,预测了在不同尺寸和温度下MoS_(2)在SiO_(2)衬底上的“脱落”条件,系统阐述了MoS_(2)与SiO_(2)衬底之间黏附性能的物理机制,为基于二维材料电子器件的优化设计提供了理论基础.
The interface adhesion properties are crucial for designing and fabricating two-dimensional materials and related nanoelectronic and nanomechanical devices.Although some progress of the interface adhesion properties of two-dimensional materials has been made,the underlying mechanism behind the size and temperature dependence of interface adhesion energy and related physical properties from the perspective of atomistic origin remain unclear.In this work,we investigate the effects of size and temperature on the thermal expansion coefficient and Young’s modulus of MoS_(2)as well as interface adhesion energy of MoS_(2)/SiO_(2)based on the atomic-bond-relaxation approach and continuum medium mechanics.It is found that the thermal expansion coefficient of monolayer MoS_(2)is significantly larger than that of its few-layer and bulk counterparts under the condition of ambient temperature due to size effect and its influence on Debye temperature,whereas the thermal expansion coefficient increases with temperature going up and almost tends to a constant as the temperature approaches the Debye temperature.Moreover,the variations of bond identity induced by size effect and temperature effect will change the mechanical properties of MoS_(2).When the temperature is fixed,the Young’s modulus of MoS_(2)increases with size decreasing.However,the thermal strain induces the volume expansion,resulting in the Young’s modulus of MoS_(2)decreasing.Furthermore,the size and temperature dependence of lattice strain,mismatch strain of interface,and Young’s modulus will lead the van der Waals interaction energy and elastic strain energy to change,resulting in the change of interface adhesion energy of MoS_(2)/SiO_(2).Noticeably,the interface adhesion energy of MoS_(2)/SiO_(2)gradually increases with MoS_(2)size decreasing,while the thermal strain induced by temperature causes interface adhesion energy of MoS_(2)/SiO_(2)to decrease with temperature increasing.In addition,we predict the conditions of the interface separation of MoS_(2
作者
段聪
刘俊杰
陈永杰
左慧玲
董健生
欧阳钢
Duan Cong;Liu Jun-Jie;Chen Yong-Jie;Zuo Hui-Ling;Dong Jian-Sheng;Ouyang Gang(Department of Physics,Jishou University,Jishou 416000,China;Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education,School of Physics and Electronics,Hunan Normal University,Changsha 410006,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第5期281-288,共8页
Acta Physica Sinica
基金
国家自然科学基金(批准号:12364007)
湖南省教育厅项目(批准号:21B0502)
国家级大学生创新创业训练项目(批准号:202210531007)
湖南省大学生创新创业训练项目(批准号:S202310531036)资助的课题.
