Study Of Preparation And Properties Of SnO₂-CdO-In₂O₃ Composite Films

Transparent conductive oxide(TCO)films have developed to the third generation with the rapid development of display screens and photovoltaic devices,it has been widely used because it can have both high visible to near infrared light transmission and good conductivity.Among them,SnO2,CdO and In2O3 are widely concerned because of their excellent optical and electrical properties.The film composed of SnO2,CdO and In2O3 three materials may obtain the best characteristics of high transmittance in visible light range and low resistivity of SnO2 films,high carrier mobility and high transmittance in near infrared range of CdO films,high electron mobility and low resistivity of In2O3 films.Therefore,this thesis used magnetron sputtering technology to prepare SnO2-CdO composite film and SnO2-CdO-In2O3 composite film,systematically studied the structural characteristics,optical characteristics and electrical characteristics of the composite film.SnO2-Cdo(4:1)films with SnO2-CdO atomic ratio of 4:1 were prepared using radio frequency(rf)magnetron sputtering.X-ray diffractometer(XRD)analysis showed that the film crystallized in Cd2SnO4(011)and SnO2(310)phases,and the crystallization performance is good,clear and sharp peaks can be seen in XRD diagram,in which Cd2SnO4(011)is the main crystallization direction;The highest transmittance of the film in the visible and near infrared range can reach 95%and 91%.The resistivity decreases as the crystal quality of the film decreases,and the lowest resistivity is 0.133 ?.cm.From the SEM images,it can be seen that the surface of the film is composed of a large number of small circular particles,and the particle distribution is uniform.The thickness of the film is estimated to be 332 nm from the SEM cross-section diagram.In order to study the effect of the ratio of SnO2-CdO on the film properties.SnO2-CdO(1:4)thin film with SnO2-CdO atomic ratio of 1:4 was prepared and compared with SnO2-CdO(4:1)thin film.The results show that the SnO2-CdO(4:1)thin film has better crystallinity and stronger optical transmittance.Using RF and DC magnetron co-sputtering technology,on the basis of better properties SnO2-CdO(4:1)film,SnO2-CdO-In2O3 composite film was prepared.XRD test results show that the thin films have diffraction peaks of Cd2SnO4(O11),SnO2(310),CdO(101),In2O3(101)and In2O3(440).As the power increase,the diffraction peaks of In2O3(101)and in2O3(440)gradually strengthen,the preferred orientation of the film changes.The diffraction peak of Cd2SnO4(011)disappears at the power of 45W.SnO2-CdO-In2O3 film has high transparency in the visible light and near infrared region,and the average transmittance exceeds 80%.The resistivity reaches 6×10-3 ?.cm when the power is 45W,which indicates that the film has good conductivity.The SEM image shows that the surface of the film is clustered by small round particles to form a large number of irregular polygonal clusters,and as the power increases,the clusters are arranged from sparse to tight.