Research On Solar-blind Photodetector Arrays Based On Diamond

Solar-blind imaging has received extensive attention in recent years due to its important role in military and civil fields,the solar-blind photodetector arrays based on ultra wide band gap semiconductor is a hot research area.As a member of the ultra wide bandgap semiconductor,diamond not only has the ultra wide band gap of 5.47 e V(located in solar-blind region),but also has good radiation resistance,high carrier mobility(>2000 cm² V^-1 S^-1),the highest thermal conductivity(>2000 W m^-1 K^-1),high breakdown electric field(>10 MV cm^-1)and excellent physical and chemical stability,etc.,become the ideal candidate material for the solar-blind photodetector arrays that work under extreme conditions,.In the preparation of photodetector arrays,a larger substrate area is needed in order to achieve a larger detection area.Although single crystal diamond has high quality,it is difficult to prepare large area photodetector arrays due to the limitation of single crystal substrate area.In contrast,polycrystalline diamond has a larger growth area,but its quality is poor.If high-quality polycrystalline diamond can be realized,it is possible to realize a larger area of solar-blind photodetector arrays,which is of great significance to realize the solar-blind photodetector arrays in extreme environment.This paper studies this problem and obtains the following results:1.Photodetector linear arrays based on polycrystalline diamond has been prepared and used for solar-blind imaging:Microwave Plasma Chemical Vapor Deposition(MPCVD)technique has been used to successfully prepare high quality 2-inch polycrystalline diamond substrate,and its quality has been characterized,which proves that polycrystalline diamond can be used for solar-blind detection.On this basis,the linear arrays of 1×10 solar blind photodetector was constructed.The linear arrays of the photodetector has good uniformity,the photo/dark current ratio is more than two orders of magnitude,the UV/Vis rejection ratio is 46,the response cutoff wavelength is 240 nm,and the detection rate is 2.92×10¹⁰ cm HZ^1/2 W^-1.By building a solar-blind imaging system,and using the linear arrays of polycrystalline diamond photodetector as the sensing unit,clear solar-blind images are obtained under different irradiation modes,which indicates that polycrystalline diamond can be used in the development of deep ultraviolet optoelectronic devices.2.A solar-blind photodetector arrays based on polycrystalline diamond was prepared and used for solar-blind imaging:A 6×6 solar-blind photodetector arrays based on 2-inch polycrystalline diamond with high quality was prepared.Through the characterization of the photodetectors properties,the photo/dark current ratio of the 36photodetector units is about two orders of magnitude,the response peak is at 218 nm,the cutoff wavelength is at 225 nm,the UV/Vis inhibition ratio is 664,the detection rate is 8.49×10¹⁵ cm Hz^1/2 W^-1,the response time is less than 10?s,and the photodetector units have good stability.Using the photodetector arrays as a sensing unit,the solar-blind imaging can be achieved without scanning.