The Study About Size Control Of 2D Material Based On Nano-Machining Method

Since graphene was first discovered in experiments in 2004,two-dimensional materials have received great attention.For example,two-dimensional materials,such as Mo S2,Sn Se and black phosphorus,exhibit physicochemical properties that are completely different from those of the bulk material and have great research prospects in the case of single layer or less layer material.The two-dimensional materials are layered structure,each atom covalently link together with other atoms and form a puckered honeycomb structure in-layer.With weak van der Waals force,monolayer material connect each other and form a stacked Multi-layer material.The excellent optoelectronic properties and direct band gap exhibited by two-dimensional nanomaterials are controlled by the number of layers and thickness of materials.Otherwise,doping is also one of the important means to study two-dimensional materials.Different doping depths also have different properties of materials.The existing methods for getting two-dimensional nanomaterials have some limitations,and it is impossible to accurately obtain specified layers material samples.Our group successfully thinned black phosphorus through AFM probe.Based on this research,we studied the mechanism of other two-dimensional materials using AFM nano-machining way is this paper.The main contents of this paper are as follows:1.As the previous nano-machining method can not control the size of twodimensional materials and doped two-dimensional materials,we proposed a twodimensional material size control method based on AFM after systematically analyzed the research status of two-dimensional materials.2.In order to protect the probe tip from damage,a tip non-destructive calibration method was proposed after ananlyzing the shortcomings of the original system.In order to accurately obtain the machining force when the AFM probe machines twodimensional materials,a cantilever torsion spring constant calibration system was developed.3.The mechanism of the thinning method was systematically studied.The interaction between AFM probe and materials surface has been analyzed in energy and mechanics respectively.We introduce the software and hardware platform of the nanomachining method.We analyzed the characteristics of machining debris from materials.4.Based on the improved software and hardware platform,the size control of the doped material was studied.The interaction between AFM probe and two-dimensional material surface in single machining experiment was studied,and the pressure threshold of machining was obtained;the influence of machining speed and interval was explored.We made circular,triangular and three-dimensional steps structure with nanomachining method.