Study On Luminescence Mechanism And Improvement Of Performance Of Tb₂O₃ Electroluminescence Devices Based On Silicon

With the continuous improvement of information technology,people's demand for information acquisition is increasing day by day.Vision,as the main way people access information,dominates 83%of the sources.Therefore,improving the level of display is crucial to getting information.As a basis for display devices,silicon-based light sources have become a research hotspot in recent years.In order to be compatible with the current mature CMOS processing technology,the silicon-based light source needs to meet the following three conditions:small lattice mismatch with silicon substrate,a low working voltage and a high luminous efficiency.The double lattice mismatch between Tb2O3 and Si is only 1.3%.The epitaxial growth of Tb2O3 film can be well compatible with single crystal Si wafer.Since Tb3+ is a highly efficient rare earth emitting ion,and Tb2O3 is a semiconductor material,an electroluminescent(EL)device based on Tb2O3 can achieve a lower operating voltage,and thus Tb2O3 is a material suitable for a silicon-based light source.At present,some progresses have been made in the research of silicon-based Tb2O3 EL devices,but the mechanism of the light emission of the devices has not been determined yet.The work,based on the previous one,through a series of experiments to explore,researched the luminescent mechanism of the Tb2O3 EL devices.By improving the structure of the device,adding the electron blocking layer and the hole injection layer in the device,the performance of the silicon-based Tb2O3 EL device is improved.Firstly,the Tb2O3 EL devices were prepared by magnetron sputtering.And the crystallization,morphology and EL properties of the devices were characterized.The luminescent mechanism of the Tb2O3 EL devices were researched by changing the materials on both sides of the electrode and the substrate and changing the direction of the electric field of the device,respectively.To reduce the loss of electrons,we added an electron blocking layer to the original device structure.In view of SiO2 and Y2O3 can effectively block the electrons and the position of their energy band are suitable,we prepared SiO2/Tb2O3 EL devices and Y2O3/Tb2O3 EL devices by magnetron sputtering.The effects of different thicknesses of SiO2 and Y2O3 on I-V curves and EL spectra of the devices were studied.In order to reduce the operating voltage and improve the electron-hole injection ratio of the device,we replaced the insulating material with the semi-conductive material and selected materials that have the function of both blocking electrons and injecting holes.We selected Ga2O3:Zn and PEDOT:PSS in inorganic and organic semiconductors respectively.Ga2O3:Zn/Tb2O3 EL devices were prepared by magnetron sputtering.The effects of different Zn2+ doping concentrations on the transmittance and band gap of Ga2O3:Zn films were investigated.After that,the effects of Zn2+ doping concentration on the I-V curves and EL spectra of the Tb2O3 EL devices were studied.In addition,we prepared PEDOT:PSS/Tb2O3 EL devices by magnetron sputtering and spin-coating.The morphologies of the devices were characterized.The influence of different thickness of PEDOT:PSS on I-V curves and EL spectra of the devices were studied.Through the above method,we found a way to effectively improve the luminescent properties of the Tb2O3 EL devices.Lastly,in view of the improvement effect of PEDOT:PSS on Tb2O3 EL devices,the PEDOT:PSS hole injection layer was applied to Tb2O3:Eu EL devices and Tb2O3:Sm EL devices.The effect of PEDOT:PSS on the luminescence of these two devices was investigated.It has been found that the hole injection layer also has an effect of improving the luminescence performance on the EL devices based on energy transfer.