Preparation And Photoelectric Properties Of Nb:SrTiO₃/ITO Heterostructures By Haser Molecular Beam Epitaxy

Indium tin oxide（SnO₂:In₂O₃≈1:9,ITO）thin films are a traditional transparent and conductive material with advantages such as low production cost,excellent electrical conductivity,and excellent light transmittance.They have been widely used in fields such as displays,sensors,and organic photovoltaic cells.At present,commercial ITO films are mostly polycrystalline or amorphous,and the quality of the films is not high.With the rapid development of the display industry and photovoltaic cell industry,more and higher requirements are being put forward for ITO films.How to improve the photoelectric performance of ITO films has become a hot research topic.The main content of this paper is to prepare high-quality ITO films and Nb-STO/ITO composite films and to characterize and analyze the structures of the prepared films.The main work and results are as follows:Firstly,ITO thin films were prepared on yttrium-doped zirconia（YSZ）substrates by laser molecular beam epitaxy（LMBE）.The effects of growth temperature and growth pressure on the structure and photoelectric properties of ITO thin films were studied.It is found that the crystallinity and surface smoothness of ITO films can be improved by increasing the growth temperature or decreasing the growth pressure.The ITO films prepared at 300°C and 0.02 Torr have the best photoelectric properties.Secondly,the experiment used LMBE technology to deposit ITO thin films on a YSZ substrate at 300°C and 0.02 Torr,and then grew niobium-doped strontium titanate（Nb:Sr Ti O₃,Nb-STO）thin films on ITO thin films to prepare Nb-STO/ITO heterostructures.The effect of growth temperature on the interface and photoelectric properties of Nb-STO/ITO heterostructures was studied.It was found that although the crystallization temperature and lattice constants of Nb-STO and ITO differ greatly,good interfacial coupling can be achieved.After depositing Nb-STO film on ITO,the light transmittance of the film decreased,but the average light transmittance was still higher than 90%.The growth temperature has little effect on the optical properties of thin films,but has a significant impact on the surface structure and electrical properties of heterostructures.When the growth temperature increases from 400℃to 700℃,the structure of Nb-STO thin films changes from amorphous to polycrystalline,and the resistance of Nb-STO/ITO heterojunction increases from 25Ω/sq to 83Ω/sq,and the electron mobility decreases from 40 cm²?V^-1?s^-1to 2 cm²?V^-1?s^-1.