Fabrication And Characteristics Of MgZnO Based Ultraviolet Detector With Microporous Ag Electrode Based On Nano Array Structure

Ultraviolet(UV)detection technology is a new technology competent for both military and civilian purposes which developed after laser and infrared detection technology.Due to the ultraviolet radiation in space,missile engine plume and high voltage line corona,ultraviolet detection technology has broad application prospects in flame detection,missile early warning,high voltage arc discharge detection,environmental monitoring,ultraviolet communication and other fields.Ultraviolet detector is the core of ultraviolet detection technology.At present,vacuum photomultiplier tube and silicon-based ultraviolet phototube have been put into commercial and military application,which is very common in recent years.In recent years,with the rapid development of wide band gap semiconductors,such as gallium nitride(GAN),zinc oxide(Zn O),silicon carbide(SIC),ultraviolet detectors based on wide band gap semiconductors have attracted extensive attention.They have the advantages of small size,low energy consumption,strong radiation resistance,intrinsic visible blindness and high stability.Therefore,wide band gap semiconductors are expected to replace the vacuum photomultiplier tubes and silicon-based ultraviolet photodetectors as a new generation of ultraviolet detection devices.Among them,Zn O has many unique properties,such as low defect density,high saturated carrier drift rate,low cost,and a wide bandgap tuning range(3.37–7.8 e V).Therefore,Mg Zn O-based materials have been regarded as some of the most promising materials for the fabrication of high performance solar-blind UV photodetectors.However,although Zn O based UV detectors have made great progress,there is still a significant gap in the comprehensive performance level and stability.In this paper,the microporous array metal film was obtained by nanosphere lithography technology in order to solve this problem,and the Zn O based UV detector based on the microporous array electrode structure was realized,which improved the UV response performance.At the same time,the stability of Zn O based UV detector was greatly improved by using organic silica gel as sealing material.The main research results are as follows:1.Single layer polystyrene(PS)spheres were prepared on the surface of the substrate by nanosphere lithography,and the size and distance of the spheres were regulated by oxygen plasma treatment.Meanwhile,the microporous array metal films were prepared by using the PS spheres as template,and their optical and electrical properties were studied.2.The Zn O based UV detector based on Ag microporous array electrode structure was constructed,and the detection performance of the device was significantly improved.Firstly,Mg Zn O thin films were prepared by MOCVD,and then Ag thin film interdigital electrodes with microporous arrays were fabricated on the Mg Zn O films by photolithography and PS sphere template.Compared with the device based on conventional metal film electrode,the optical responsivity of Zn O based UV detector based on micro hole array interdigital electrode was increased by 200%.This work shows that the microporous array electrode has an important potential application in the preparation of high performance UV detector.3.The encapsulation of Zn O based UV photodetectors was studied for the first time.Organic silica gel was used as the sealing material to package the Zn O based UV photodetectors.After being packaged,the responsivity of the device was improved,and the response speed was slightly decreased,but its stability was obviously improved.After a long time of storage,the responsivity and response time are basically unchanged,which further promotes the practical process of Zn O based UV detector.