Preparation And Photoelectric Properties Of Infrared Devices Based On PbSe Thin Films

Lead selenide(PbSe)is a kind of IV-VI lead salt semiconductor compound.Its band gap is 0.2 e V to 0.4 e V at room temperature.It is a common narrow band gap semiconductor material and has attracted much attention in the field of infrared detectors.At present,devices prepared from PbSe thin films have attracted extensive attention.However,considering the disadvantages of large dielectric constant and low carrier mobility,the further development of PbSe materials in the field of infrared detection has been hindered.In thesis,a variety of preparation processes of PbSe thin film are studied,the characteristics of the material are analyzed and characterized in detail,the photoelectric properties of the device are optimized by sensitization and structural design,and the infrared detector based on PbSe thin film is deeply studied.The main research contents of thesis are as follows:(1)PbSe thin films were prepared by chemical bath deposition.The effects of growth time and p H value on the microstructure and photoelectric properties of the films were investigated.It is found that the chemical bath deposition method has good controllability and operability.When the growth time is 30 min and the PH value of the deposition solution is 10.0,the crystal growth quality of the film is the best,and the photoelectric performance of the device is the best year-on-year.It is found that the responsivity and detection rate of the photoelectric device prepared by PbSe film under this parameter to 1550 nm short wave infrared light are 36 m A/W and 3.1×10~9Jones.(2)The sensitization treatment and photoelectric performance improvement of PbSe thin films were studied.Due to the low sensitivity of the initially prepared films,thesis sensitizes them in iodine vapor atmosphere according to the doping mechanism,and studies the microstructure,composition and photoelectric properties of the sensitized films.It is concluded that due to the introduction of iodine atoms,the surface polarity of PbSe films changes,resulting in the critical state of PN junction,resulting in the orderly separation and transmission of most carriers and increasing the response photocurrent,The performance of the infrared photodetector is improved by Pb.It is found that the responsivity and detection rate of the photoelectric device prepared by sensitized PbSe film to 1550 nm short wave infrared light are 117 m A/W and 1.16×10¹⁰Jones.The results show that the sensitization treatment can significantly improve the response and detection rate of the device.(3)A photodetector with PbSe/graphene double-layer planar structure was designed and fabricated.Considering the limitation of low mobility of PbSe material,the structure of PbSe detector has been innovated and improved in thesis.With the help of graphene's ultra-high carrier mobility,the responsiveness of the device has been greatly improved,and the dark current and noise have been suppressed to a certain extent.It is found that the response and detection rate of PbSe/graphene detector with double-layer plane structure to 1550 nm short wave infrared light are 683 A/W and8.4×10~9Jones.Compared with single-layer PbSe devices,the response speed and responsiveness are significantly improved.