Research On The Key Technology Of Preparation System Of Graphene By Laser-chemical Vapor Deposition

Graphene(Graphene,GP)is a hexagonal honeycomb two-dimensional carbon atom crystal,which has unique structure and excellent properties.Within a few years of graphene discovery,its excellent mechanical,optical,thermal,and electrical properties have been discovered,which has stimulated its potential applications.The synthesis and preparation methods of graphene have been explored and perfected.At present,the commonly used preparation methods have different degrees of defects,and can not be compatible with the semiconductor technology.And there are still many technical difficulties in the preparation of graphene and the control of the number of layers.Based on this,this paper introduces the laser technology in the preparation of graphene,using laser chemical vapor deposition(Laser-chemical vapor deposition,LCVD)to explore the preparation process of graphene.The main work of this paper is:1?Based on the principle of LCVD preparation of graphene and the basis of the existing equipment in the laboratory,this paper has carried on the optimization design of the LCVD method to prepare graphene device.The design mainly includes three parts,the design of total pipeline,using the design of automatic control system and monitoring system for the preparation of LCVD graphene,and the design of automatic monitoring and control software for the device.2?In order to improve the efficiency of graphene preparation,the experiment based on two point method was designed to detect the quality of laser beam divergence angle.According to the test results,the corresponding beam shaping scheme is designed.According to the design scheme,the optical element is selected,and then the optical fiber structure is processed.After processing,the beam shaping mechanism is applied in the experiment,and it can effectively reduce the laser beam divergence angle and improve the laser beam quality.3?In order to assist in the monitoring of the laser focusing state in the preparation of graphene,On the basis of the monitoring software,the algorithm of spot detection is designed in this paper.Based on the least square method,the center of the spot and the size of the substrate are obtained,and the detection accuracy is improved.These results provide an auxiliary monitoring function for the preparation of graphene.4?In this paper,copper foil was used as the growth substrate of graphene,and graphene was prepared on the LCVD experimental platform.According to Raman sample test results,this paper analyzes the quality formation mechanism of graphene,the growth conditions and the existing problems,which provide reference for the experiment to carry out the next step.In this paper,LCVD method was used to prepare graphene and when the laser moving velocity is less than 20,P=3W,the pre chamber pressure is less than 10mTorr,the preparation pressure of 500mTorr;gas flow rate VH2=10sccm and VCH4=5sccm can be prepared to get a few layers of graphene film.Graphene layers,quality and growth area can be controlled by controlling the experimental conditions,the effective optimization of the graphene preparation process for patterned graphene preparation,graphene semiconductor integration provides the process base.