Preparation And Optical And Electrical Properties Of Ba_1-xLa_xSnO₃ Transparent Conductive Films

In recent years,transparent conductive films have been widely used in optics,electronic information and other aspects,such as solar cells,flat displays,light-emitting diodes,etc.so the market demand for transparent conductive films is increasing.How to prepare non-toxic and cost-effective transparent conductive film has become a hot research topic.Currently,ITO and FTO films are the most widely used transparent conductive films.However,due to the rising price of metal indium and the corrosive nature of F ions,it is extremely urgent to find a transparent conductive film with excellent performance to replace ITO and FTO films.Perovskite oxide has become a new type of transparent conductive film due to its simple structure and easy doping,and has many excellent physical properties,such as piezoelectric,ferroelectric,photoelectric effect,etc.among them,barium stannate has a wide band gap,and its cubic structure is easy to doping.It has become a perovskite oxide that has been studied more in recent years.At present,many research groups have studied the preparation process and properties of barium stannate thin films doped with Sm,Nd,Gd,Ta and other elements,but the preparation process and doping amount of barium stannate without La doping have not been systematically studied.Therefore,in this paper the doping amount of barium stannate doped La film was studied in a larger range and the preparation process was optimized to obtain better performance.In order to explore the effect of different doping amount and preparation process on the photoelectric properties of Ba_1-xLa_xSn O₃ thin films,STO（Sr Ti O₃）single crystal was selected as the substrate and pulse laser deposition technology was adopted.Grow in STO substrate Ba_1-xLa_xSn O₃（x=0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12）transparent conductive film two aspects of the research content is as follows:（1）To explore the effect of doping concentration on the properties of the films under the same preparation process,we prepared Ba_1-xLa_xSn O₃target with different doping concentration by solid state reaction method.By using pulse laser deposition technology,the oxygen partial pressure was adjusted to 13 Pa,the substrate temperature was 750 ^oC,the film sputtering time was 45 min,and the sputtering frequency was 2Hz.The laser energy is 220 m J.After sputtering,the fire was in situ for 30 min.Ba_1-xLa_xSn O₃films with different doping amounts were prepared by cooling them to room temperature at a cooling rate of 10 ^oC/min.It was found that with the increase of doping concentration,the crystallinity and photoelectric properties of BLSO films improved obviously.When the doping content is 7%,the overall performance of the film is the best,the resistivity is 0.75 mΩcm at room temperature,and the mobility is 22.75 cm²V^-1s^-1.The transmittance is up to 85%in visible region.Therefore,we selected Ba_1-xLa_xSn O₃film with 7%La doping content to optimize the preparation process,so as to obtain Ba_0.93La_0.07Sn O₃ film with better performance.（2）Under the premise of optimal doping concentration of Ba_0.93La_0.07Sn O₃ target,BLSO thin films were deposited on STO（001）single crystal substrate by pulse laser deposition technology.The effects of oxygen pressure,deposition temperature and preparation time on the structure and properties of the thin films were investigated.It was found that the preparation temperature of 825 ^oC,oxygen pressure of 5 Pa and sputtering time of 37.5 min were the best preparation conditions of BLSO.Under these conditions,the properties of the films reached the best,the crystallinity of the films was the best,the full width at half maximum of the swing curve was about 0.05^o,and the resistivity of the films at room temperature was 0.33 mΩcm.The mobility is about35.39 cm²V^-1s^-1,and the transmittance in visible region is about 85%.The results of this experiment lay a foundation for the further development of barium stannate thin film in perovskite transparent conductive thin film.