Synthesis Of Nitrogen And Sulfur Co-Doped Graphene For Photoelectric Applications

Graphene is the thinnest two-dimensional atomic crystal material that sp²hybrid carbon atoms are arranged in a honeycomb structure.It is also the perfect two-dimensional nanomaterial.Its discovery is another legend of the carbon material family.Early theory and experiments all believed that two-dimensional materials could not exist in a free state.But it's a misconception and this misconception has been overturned.In the new nanomaterials world,a global technological revolution is being triggered.This revolution is still heating up and progress,without any sign of cooling down.Graphene's mechanical,electrical and thermal conductivity are outstanding among many nanomaterials.At the same time,it has the flexibility and stability of two-dimensional lattice structure and extremely high transparency of monoatomic layer.It will be applied in many fields such as new materials,new energy,microelectronics,intelligence,medicine,aerospace and so on.In the past decade,the preparation methods of graphene have been characterized by mechanical cleavage,graphite oxide reduction,epitaxy growth of silicon carbide?SiC?,chemical vapor deposition?CVD?,plasma enhanced chemical vapor deposition?PECVD?.Among many methods,CVD method has been endowed with a unique advantage and has become the mainstream preparation method of graphene.By CVD method,large area and controllable layers of uniform and high quality graphene can be prepared on metal substrates with catalytic ability,and it has great application prospects due to its transfer ability to arbitrary substrates.However,intrinsic graphene is a semiconductor material with zero band gap,which greatly limits its application in many fields.To improve the properties and applications of graphene,domestic and foreign researchers try to modify or open the band gap of graphene.Among these methods,doping is an effective modification method,which can not only open the band gap of graphene,but also regulate the electrical,chemical,optical and magnetic properties of intrinsic graphene materials.This paper is based on the current research background of doped graphene materials reported by the scientific research community.In view of the challenges faced in the preparation technology,it focuses on the preparation of doped graphene.The preparation of doped graphene materials can be controlled by CVD method assisted by graphene quantum dot nucleation.The main research contents are as follows:Nitrogen and sulphur co-doped graphene quantum dots?N&S-GQDs?are used as single doping source and nucleation seeds to spin-coat on annealed Cu foil.Then nitrogen and sulphur co-doped graphene?N&S-G?thin films can be grown by placing Cu substrate containing N&S-GQDs in a CVD tubular furnace.Subsequently,it will be transferred to the silicon dioxide?SiO₂?substrate and applied to field effect transistors and photodetectors to characterize the structure and properties of N&S-G by various means.The doping concentration of nitrogen and sulfur in graphene can be adjusted by changing the spin-coating speed.This can achieve a green controllable preparation method with uniform doping and large area graphene films,which breaks through the limitation of high-temperature preparation of doped graphene.In this paper,N&S-G thin films are used in photodetectors to achieve high sensitivity at 1550nm,and this nucleation seed-assisted growth method has broad application prospects in the preparation of doped graphene.