Synthesis Of Two-dimensional Layered Molybdenum Disulfide By Chemical Vapor Deposition

Recently,a growing number of two-dimensional materials draw a great attention and are studied,which have a large potential in the applications of new type semiconductor devices.What's more,this kind of 2D materials provide an opportunity for people to make a continuation of existing Moore's Law.Among these kinds of 2D materials,molybdenum disulfide has attracted a mountain of attention and studies.Two-dimensional layered molybdenum disulfide has become research focus because of its special layered structure and naturally occurring band gap.However,it is still a difficulty to obtain large area layered molybdenum disulfide which is the prerequisite for the application of molybdenum disulfide in semiconductor devices.This dissertation is focused on the investigation of synthesis of layered molybdenum disulfide with the method of chemical vapor deposition.The specific contends are as follows:(1)The effect of growth temperature in the growth results is studied in the substrate of Si/SiO2 by chemical vapor deposition.It is found that the sizes of molybdenum disulfide synthesized at the temperature of 650 ? are larger than those of other temperatures.Many of molybdenum disulfide flakes appear in the substrate with the growing time of 10 mins,and the sizes of these flakes are from 50?m to 100?m.(2)The effect of seed promoters concentration coated in the clean substrates in the growth results is researched.From the experiments,we can find that when the concentration of seed promoters coated in the substrate is 1.5×10-7mg/L,the size of the molybdenum disulfide flakes synthesized in the substrate is the biggest.Besides,the neighboring flakes do meet together and have no trend to overlap one another.In this condition,the sizes appear in the substrate are from 80?m to 100?m.(3)The effect of carrier gases in the growth results are studied by using different gases in the experiments.Two kinds of carrier gases are utilized during the experiments,nitrogen and argon.From the results,we can find that the sizes of molybdenum disulfide flakes using argon are two times larger than those using nitrogen.