Preparation And Device Research Of The Graphene And New Semiconductor Materials Heterostructure

Graphene,wide-gap semiconductor and new two-dimensional semiconductor materials have their own excellent structural properties,photoelectric properties and broad application prospects,while they have their own limitations.In recent years,the fabrication and device applications of graphene,wide band gap semiconductor and two-dimensional materials have become a hot research topic.This kind of heterogeneous structure can complement each other in nature,give full play to the advantages of materials,and achieve excellent application performance.Although many research groups have made progress in related fields,there are still many aspects worthy of further study,such as new methods of heterostructure preparation and performance optimization.Based on the heterojunction preparation of graphene,GaN,SiC,diamond and black phosphorus,and the application of photoelectric detector,the properties of these materials and the optimization of photoelectric performance are discussed in this paper.The following research work was carried out:（1）Preparation of high quality graphene films by CVD segregation and study on the preparation of graphene and GaN heterostructures.A method of graphene segregation and synthesis by etching of H₂on Ni film was proposed.The experimental design and synthesis process of this method were briefly described.The high quality and excellent electrical properties of the synthesized graphene have been further proved by the fabrication and test of Hall devices.Then by using novel MMA migration technology,the synthesized graphene was transferred to GaN substrate to form a heterostructure.The basic properties of the heterostructure were verified by relative characterization tests.（2）The epitaxial growth of the heterostructure between graphene,SiC and diamond has been futher studied.The growth of epitaxial SiC was studied on the basis of high temperature CVD.High quality epitaxial SiC-graphene heterostructure was obtained by one-furnace-two-step epitaxial SiC substrate.Then we realized the first time to produce high quality graphene by epitaxy on SiC using MPCVD.Diamond on SiC,diamond on SiC-graphene and graphene directly grown on target substrate were fabricated by MPCVD.（3）With graphene-GaN as the representative heterostructure,the preparation and characterization of the Schottky ultraviolet photodetector and the detection performance in the ultraviolet band were futher studied.The slow damage etching of GaN was realized and the effect of GaN slow damage etching on Schottky structure was studied.The graphene-GaN vertical Schottky ultraviolet photodetector was fabricated based on the CVDSG and GaN slow etching surface treatment,and its UV detection performance was measured.Then to achieve the optimization of ultraviolet detection performance,graphene-GaN nano-column structure of the Schottky ultraviolet photodetector was further fabricated.（4）In order to realize the expansion of photodetectors in the visible and infrared bands,the heterostructures of graphene and black phosphorus were fabricated by the van der Waals stacking method,and photodetectors were fabricated by the upper electrode method and the lower electrode method.By comparing the photoelectric detection performance in visible light band,the advantages of using Mo as the electrode were verified.Furthermore,the performance of the device was studied in infrared band,and graphene black phosphorus photodetector with high sensitivity and wide range from visible to middle infrared band was realized.