用动力学晶格蒙特卡洛模型(Kinetic Lattice Monte Carlo,KLMC)模拟Cu薄膜的生长过程,讨论了基底温度、沉积原子数、单原子最大迁移步数和原子相互作用范围等参数对薄膜表面形貌的影响,并与实验结果进行了比较。结果表明:基底温度升高...用动力学晶格蒙特卡洛模型(Kinetic Lattice Monte Carlo,KLMC)模拟Cu薄膜的生长过程,讨论了基底温度、沉积原子数、单原子最大迁移步数和原子相互作用范围等参数对薄膜表面形貌的影响,并与实验结果进行了比较。结果表明:基底温度升高或沉积原子数增加时,沉积在基底上的原子逐步由众多各自独立的离散型分布向聚集状态过渡形成团簇,并且温度越低,团簇越趋于分散生长。当最大迁移步数减小或相互作用范围增大时,团簇亦趋于分散生长。展开更多
Interface and surface physics is an important sub-discipline within condensed matter physics in recent decades. Novel concepts like oxide-electronic device are prompted, and their performance and lifetime are highly d...Interface and surface physics is an important sub-discipline within condensed matter physics in recent decades. Novel concepts like oxide-electronic device are prompted, and their performance and lifetime are highly dependent on the flatness and abruptness of the layer surfaces and interfaces. Reflection high-energy electron diffraction （RHEED）, which is extremely sensitive to surface morphology, has proven to be a versatile technique for the growth study of oxide thin films. A differential pumping unit enables an implementation of RHEED to pulsed laser deposition （PLD） systems, ensuring an in situ monitoring of the film growth process in a conventional PLD working oxygen pressure up to 30 Pa. By optimizing the deposition conditions and analyzing the RHEED intensity oscillations, layer-by-layer growth mode can be attained. Thus atomic control of the film surface and unit-cell control of the film thickness become reality. This may lead to an advanced miniaturization in the oxide electronics, and more importantly the discovery of a range of emergent physical properties at the interfaces. Herein we will briefly introduce the principle of high-pressure RHEED and summarize our main results relevant to the effort toward this objective, including the growth and characterization of twinned Laz/3Caj/3MnO3 thin films and ReTiO〉6/2 （Re = La, Nd; ~5 = 0 - 1） AnBnO3n＋2 structures, on YSZ-buffered ＇Silicon on Insulator＇ and LaA103 substrates, respectively, as well as the study of the initial structure and growth dynamics of YBazCu307-6 thin films on SrTiO3 substrate. Presently we have realized in situ monitoring and growth mode control during oxide thin film deposition process.展开更多
Transferring MoS2 films from growth substrates onto target substrates is a critical issue for their practical applications. Moreover, it remains a great challenge to avoid sample degradation and substrate destruction,...Transferring MoS2 films from growth substrates onto target substrates is a critical issue for their practical applications. Moreover, it remains a great challenge to avoid sample degradation and substrate destruction, because the current transfer method inevitably employs a wet chemical etching process. We developed an etching-free transfer method for transferring MoS2 films onto arbitrary substrates by using ultrasonication. Briefly, the collapse of ultrasonication-generated microbubbles at the interface between polymer-coated MoS2 film and substrates induce sufficient force to delaminate the MoS2 films. Using this method, the MoS2 films can be transferred from all substrates （silica, mica, strontium titanate, and sapphire） and retains the original sample morphology and quality. This method guarantees a simple transfer process and allows the reuse of growth substrates, without involving any hazardous etchants. The etching-free transfer method is likely to promote broad applications of MoS2 in photodetectors.展开更多
For the first time we fabricated ZnO membranes with thicknesses of 2.4 nm by a facile one-pot synthesis in aqueous solution.The crystal analysis revealed that the hexagonal ZnO membranes were about 10 atomic layers in...For the first time we fabricated ZnO membranes with thicknesses of 2.4 nm by a facile one-pot synthesis in aqueous solution.The crystal analysis revealed that the hexagonal ZnO membranes were about 10 atomic layers in thickness.The ZnO membranes bent,scrolled,intersected with each other,and self-assembled to particles in micrometre size.The hierarchical assemblies showed sponge-like structures with room inside.In the growth process,a cationic polyelectrolyte was utilized to modulate growth behavior of the ZnO crystals.As a result,the preferred growth direction of ZnO membranes is along 0110,which was perpendicular to[0001]growth direction in a typical hydrothermal synthesis.The growth mechanism of the membranes was also discussed.展开更多
文摘用动力学晶格蒙特卡洛模型(Kinetic Lattice Monte Carlo,KLMC)模拟Cu薄膜的生长过程,讨论了基底温度、沉积原子数、单原子最大迁移步数和原子相互作用范围等参数对薄膜表面形貌的影响,并与实验结果进行了比较。结果表明:基底温度升高或沉积原子数增加时,沉积在基底上的原子逐步由众多各自独立的离散型分布向聚集状态过渡形成团簇,并且温度越低,团簇越趋于分散生长。当最大迁移步数减小或相互作用范围增大时,团簇亦趋于分散生长。
基金supported by the National Natural Science Foundation of China(Grant Nos.10974229 and 11174342)
文摘Interface and surface physics is an important sub-discipline within condensed matter physics in recent decades. Novel concepts like oxide-electronic device are prompted, and their performance and lifetime are highly dependent on the flatness and abruptness of the layer surfaces and interfaces. Reflection high-energy electron diffraction （RHEED）, which is extremely sensitive to surface morphology, has proven to be a versatile technique for the growth study of oxide thin films. A differential pumping unit enables an implementation of RHEED to pulsed laser deposition （PLD） systems, ensuring an in situ monitoring of the film growth process in a conventional PLD working oxygen pressure up to 30 Pa. By optimizing the deposition conditions and analyzing the RHEED intensity oscillations, layer-by-layer growth mode can be attained. Thus atomic control of the film surface and unit-cell control of the film thickness become reality. This may lead to an advanced miniaturization in the oxide electronics, and more importantly the discovery of a range of emergent physical properties at the interfaces. Herein we will briefly introduce the principle of high-pressure RHEED and summarize our main results relevant to the effort toward this objective, including the growth and characterization of twinned Laz/3Caj/3MnO3 thin films and ReTiO〉6/2 （Re = La, Nd; ~5 = 0 - 1） AnBnO3n＋2 structures, on YSZ-buffered ＇Silicon on Insulator＇ and LaA103 substrates, respectively, as well as the study of the initial structure and growth dynamics of YBazCu307-6 thin films on SrTiO3 substrate. Presently we have realized in situ monitoring and growth mode control during oxide thin film deposition process.
基金Acknowledgements This work was financially supported by the National Natural Science Foundation of China （Nos. 51222201, 51290272, 51472008, and 51432002）, the National Basic Research Program of China （Nos. 2012CB921404, 2013CB932603, 2012CB933404, and 2011CB921903）, and the Foundation for Innovative Research Groups of the National Natural Science Foundation of China （No. 51121091）.
文摘Transferring MoS2 films from growth substrates onto target substrates is a critical issue for their practical applications. Moreover, it remains a great challenge to avoid sample degradation and substrate destruction, because the current transfer method inevitably employs a wet chemical etching process. We developed an etching-free transfer method for transferring MoS2 films onto arbitrary substrates by using ultrasonication. Briefly, the collapse of ultrasonication-generated microbubbles at the interface between polymer-coated MoS2 film and substrates induce sufficient force to delaminate the MoS2 films. Using this method, the MoS2 films can be transferred from all substrates （silica, mica, strontium titanate, and sapphire） and retains the original sample morphology and quality. This method guarantees a simple transfer process and allows the reuse of growth substrates, without involving any hazardous etchants. The etching-free transfer method is likely to promote broad applications of MoS2 in photodetectors.
基金supported by the Ministry of Science and Technology of China(Grant Nos.2013CB933604 and 2010CB934203)the National Natural Science Foundation of China(Grant Nos.61171023 and 61076057)
文摘For the first time we fabricated ZnO membranes with thicknesses of 2.4 nm by a facile one-pot synthesis in aqueous solution.The crystal analysis revealed that the hexagonal ZnO membranes were about 10 atomic layers in thickness.The ZnO membranes bent,scrolled,intersected with each other,and self-assembled to particles in micrometre size.The hierarchical assemblies showed sponge-like structures with room inside.In the growth process,a cationic polyelectrolyte was utilized to modulate growth behavior of the ZnO crystals.As a result,the preferred growth direction of ZnO membranes is along 0110,which was perpendicular to[0001]growth direction in a typical hydrothermal synthesis.The growth mechanism of the membranes was also discussed.
