Study On Amorphous ZnSnO₃ Ultraviolet Photoelectric Sensor Based On Light-induced Homostructures

Ultraviolet(UV)detection technology is almost unaffected by environmental background noise,and has been widely used in bioanalysis,transmitter calibration,space detection,etc.And UV photosensors are the core of technology.Nowadays,UV photosensors are mainly based on monoatomic silicon,Group ? nitride and metal oxide materials.Silicon and ?-nitrides are costly,complex to prepare,so its development is limited.Wide-bandgap metal oxide semiconductor materials,such as binary oxides such as ZnO and SnO₂,and ternary oxides such as Zn Ga₂O₄ and ZnSnO₃,also have good UV photosensitivity to ultraviolet light,and their physicochemical properties are stable,preparation cost is low,and transmittance of visible light is high.So it has become a research hotspot in the field of ultraviolet photodetectors.The ternary oxide structure is stable and can be widely concerned by changing its composition to adjust the function of the oxide flexibly.The UV photosensitive material ZnSnO₃ has the advantages of both ZnO and SnO₂,and has wide application prospects in the field of photoelectronic devices,but its photoelectric properties are susceptible to the preparation process.In this paper,high purity Zn Sn(OH)₆ particles were synthesized by coprecipitation method and hydrothermal method,in which Na OH was used as precipitant and HTMA was used as organic functional additive.SAEM and TEM analysis showed that the synthesized Zn Sn(OH)₆ precursor was polycrystalline cube,and the corresponding ZnSnO₃semiconductor material obtained by high temperature treatment was amorphous.The experimental comparison shows that the photoelectric performance of ZnSnO₃obtained by hydrothermal method is better than that of coprecipitation method.Therefore,the research focused on the photoelectric properties of ZnSnO₃ obtained by the former.In addition,the performance of ZnSnO₃ can be flexibly controlled by its Zn Sn(OH)₆precursor,which is confirmed by Mg²⁺doping of Zn Sn(OH)₆.The photoelectric properties of the Mg dopant obtained by hydrothermal method are significantly improved.The photo-dark current ratio of Zn_0.9Mg_0.1SnO₃ photoelectric sensor is 10715(3.3 V,UV:2.46 m W/cm²),and the response and recovery speed are4 s and 9 s,respectively.It also showed good linearity and stability.According to the mechanism research,it is believed that the reasons for its good optoelectronic properties is the formation of photoinduced homojunction in ZnSnO₃ due to the difference of oxygen vacancies and the inhibition of photoelectron and hole recombination are.When used in imaging,UV photosensors need to be arrayed and provided with appropriate readout circuit.Based on the photoelectric performance test,a 2×2 array model of Zn_0.9Mg_0.1SnO₃ ultraviolet photoelectric sensor was established,and a CMOS read-out circuit including capacitive feedback transimpedance amplifier(CTIA)type readout and correlated double sampling was designed.The read-out circuit is simulated with 0.25?m 1-poly 5-metal process.It costed 80?s to complete readout of signals of the whole array.The read-out circuit can accurately convert photocurrents from 10 n A to 16?A.The op amp in circuit consumes 815.5?W.The simulation results indicate that the designed readout circuit can quickly read out electrical signals of the 2×2 sensor array with low power consumption.