Preparation And Photoelectric Properties Of Flexible O/M/O Transparent Thin Film Electrodes On PET Substrates

Compared with single layer transparent conducting oxide(TCO)films,the hybrid films with a structure of thin metal film layer between two oxide layers named Oxide-Metal-Oxide(OMO)have a series of advantages such as,reduce the overall thickness of films,increase the flexibility,conductive to industrial production,have better stability,etc.However,it is difficult to obtain a film having good conductivity and light transmittance due to the addition of the metal layer.It is an important way to improve the photoelectric performance of the thin film by modifying the middle layer metal by doping to change the growth mode of the metal thin film on the oxide and obtain the ultra-thin continuous metal film.In this paper,the OMO structure thin film electrode was deposited on the flexible substrate by means of room temperature magnetron sputtering.The deposition time and the oxygen flow rate were studied by the method of reactive magnetron sputtering when the interlayer metal A1 film was deposited.The surface morphology,optical properties and electrical properties of the films were investigated.The intrinsic relationship between the photoelectric properties of the films and the microstructure and surface morphology of the films was analyzed,and the optimum preparation conditions of the films were explored.In this paper,the ITO-AI-ITO structure thin film electrode were prepared on PET,the bottom and top ITO thickness is only about 20 nm,the overall thickness of the film is 50-70 nm,the film has greatly improved flexibility.The growth process of Al film on ITO surface was studied by FESEM and AFM.It was found that A1 was grown on the surface of ITO with obvious granule.After the micro-doping of the intermediate layer,the Al film grows from three-dimensional granular growth to two-dimensional lamellar growth.When the oxygen flow rate is 0.4-0.8 sccm,the film reaches the optimal surface morphology.After the oxygen doping,the transmittance of ITO-AlOx-ITO film increases in the short wavelength(350-550 nm)and decreases in the long wavelength(550-1000 nm).The full-wavelength average transmittance increases after all.The results of electrical properties show that the electrical properties of the films are optimized with the increase of the interlayer deposition time.The electrical properties deteriorate as the doping amount increases.ZnO-Al-ZnO transparent conductive thin film electrode without In was prepared by replacing ITO with ZnO.The morphology results show that when Al grows on the surface of ZnO,grain is more small,dense and uniform.When the deposition time of the middle layer is 30s,the maximum transmittance of the film is only 51%.The average transmittance of 400-1000 nm is 37%,the square resistance is 20.05 Ω·sq-1,the carrier concentration is 3.55 ×1017 cm-3,and the mobility is 3.82 cm2V-1s-1.After oxygen doping,the transmittance of ZnO-AlOx-ZnO thin films increases in the long wavelength range and decreases in the short wavelength range,and the average transmittance increases.When the oxygen flow rate is 0.4 sccm,the sheet resistance is 55.82 ·Ωsq-1,the carrier concentration is 3.62×1016 cm-3,and the mobility is 3.95 cm2V-1s-1.