Performance Of Photodetector Based On Cd₃As₂/organic Heterojunction

The excellent properties of Dirac semimetal,such as high mobility,high conductivity,zero band gap,and high absorption rate,make it occupy an important position in the development of a new generation of photodetectors.As a typical three-dimensional Dirac semimetal material,Cd₃As₂ has the properties of ultra-high carrier mobility(?10⁵),high broadband absorption rate(30%-50%),fast electron transmission speed and high photocurrent response,which provides a good platform for manufacturing high-performance photodetectors.In this paper,the performance of the photodetector based on Cd₃As₂ film is studied,and performance indicators such as response current,response rate and response time of the Cd₃As₂ based photodetector are optimized by doping and constructing heterojunctions.The main research contents of this paper are as follows:(1)By studying the photoelectric properties of Cd₃As₂ thin film devices,it is found that due to the high light absorption and high carrier mobility of Cd₃As₂ thin films,the devices have good photocurrent response from visible light to near infrared.But at the same time,the device also has the problem of too large dark current,which limits the application of Cd₃As₂ thin film in low current detection.Furthermore,a photodetector based on Cd₃As₂/Pb Pc heterojunction is designed.Heterojunction devices have good rectifying characteristics,which conform to the characteristics of diodes.Compared with thin film devices,the dark current decreases significantly,especially under negative bias.The device has good photocurrent response in visible near infrared region.The specific detection rate and response time of the device are greatly improved,and the maximum specific detection rate is 3.05×10¹¹ Jones,and the response time is 160/170?s.Heterojunction photodetectors based on Cd₃As₂ thin film have different photoelectric detection performance parameters due to different organic compounds.The performance of devices can be adjusted by changing the way of organic compounds,which provides an idea for functional Cd₃As₂ thin film heterojunction photodetectors.(2)By studying the photoelectric properties of(Cd_1-xZn_x)₃As₂ thin film devices,it is found that the dark current of(Cd_1-xZn_x)₃As₂ thin film is about 10 times lower than that of Cd₃As₂ thin film,but the light current is only half lower at the same time.Similarly,the device has good photocurrent response from visible light to near infrared.Therefore,(Cd_1-xZn_x)₃As₂ thin films have more potential applications.Then a photodetector based on(Cd_1-xZn_x)₃As₂/Pb Pc thin film heterojunction is designed.The device has good rectifying characteristics,and the rectifying ratio is more than 1000.Compared with Cd₃As₂/Pb Pc thin film heterojunction device,the dark current of(Cd_1-xZn_x)₃As₂/Pb Pc thin film heterojunction device is reduced by 7 times,and the photocurrent changes little,so the device performance is significantly improved.The specific detection rate of(Cd_1-xZn_x)₃As/Pb Pc thin film heterojunction device is 3.95×10¹¹ Jones,and the response time is 80/100?s.(3)(Cd_1-xZn_x)₃As₂/semiconductor/(Cd_1-xZn_x)₃As₂ linear photodetector was designed and fabricated.Organic semiconductor Pb Pc and inorganic semiconductor MoO₃ were selected as intermediate transport channels.Due to the low carrier mobility of the intermediate channel materials and the existence of symmetrical heterojunction at both ends of the channel,the dark current of the line array devices is reduced to the order of10^-10 A.Moreover,the photocurrent of(Cd_1-xZn_x)₃As₂/MoO₃/(Cd_1-xZn_x)₃As₂ unit device can also be detected at 5?m band,which further verifies the wide spectral absorption of the film.In addition,the unit device has good stability and repeatability.These results show that the array devices based on Dirac semimetal have great application potential in the field of infrared detection in the future.