Study On Ultraviolet Detection Performance Of Delafossite Materials

A photodetector is a device that converts light radiation into electrical signals.It can be divided into ultraviolet detection,infrared detection and wide-broad detection.Ultraviolet photodetectors have received widespread attention due to their high sensitivity and fast time response.Because of strong radiation tolerance,high thermal conductivity,high breakdown electric field strength,high electron mobility and good chemical stability,wide band gap semiconductor materials have become the representative materials for the preparation of ultraviolet photodetectors.The two-dimensional p-type delafossite materials conduct elec-tricity with holes,and the band gap width is greater than the upper limit of visible photon energy of 3.11 e V.The band gap of CuGaO₂ microplates is 3.7 e V,doping different ele-ments(Zn/Cr)could improve the hole concentration and tune the optical properties of CuGaO₂.Lattice matched CuGaO₂ microplates and Zn O microwires can construct hetero-junction,which is a method to improve device performance.Therefore,this thesis mainly studies the detection performance of CuGaO₂ microchip,the specific research contents are as follows:(1)Two-dimensional semiconductor materials were synthesized via a facile hydro-thermal reaction,including CuGaO₂ microchips,Zn doped CuGaO₂microplates,Cr doped CuGaO₂ microplates and CuGaO₂/Zn O heterojunction.Scanning electron microscopy(SEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and Energy Dispersive Spectrometer(EDS)were used to characterize and analyze the properties of the materials.(2)Study on ultraviolet detection performance of Zn doped CuGaO₂ microplates.Metal mask combined with magnetron sputtering process to fabricate the detectors on a Si substrate.And then compared the performance of UV detection based on CuGaO₂ micro-plates and Zn doped CuGaO₂/Zn O heterojunction.The results demonstrated that the re-sponse value of the detector fabricated by the heterojunction was 4 times that of the CuGaO₂ microplates,and its sensitivity was 23 times that of the CuGaO₂ microplates.(3)Study on wide-broad detection performance of Cr doped CuGaO₂ microchips.ul-traviolet lithography combined with magnetron sputtering to fabricate detectors on Si O₂/Si substrate.The photocurrent,phototo-current ratio and responsivity values of the device based on Cr doped CuGaO₂ microplates were measured under the three different wave-lengths(365nm/620nm/940nm)illumination.Experimental results show that the photocur-rent value of the devices was greater than the dark current and the illumination response speed was milliseconds.It proved that Cr doped CuGaO₂ microplates is suitable for wide-broad detection.(4)Study on the enhancement of ultraviolet detection performance of Cr doped CuGaO₂ microplates.Detector performance was enhanced by the localized surface plasmon resonance effect of Ag nanoparticles.Ag nanoparticles modified CuGaO₂/Zn O heterojunc-tion on Si O₂/Si substrate and quartz substrate,respectively.It turned out that the detector modified by Ag nanoparticles had the most prominent photoelectric performance,and its response value reached 174.9 m A/W.Therefore,CuGaO₂ microplates is eligible to be a candidate materials for ultraviolet and wide-broad photodetectors,which provides a new way for the design of new photoe-lectric devices.