Preparation And Optical-electro Properties Of Sb-doped And Co-doped SnO₂ Thin Films

Tin dioxide(SnO2) is a wide-band-gap semiconducter(-3.6eV) and the binding energy of the exciton is about 130meV. SnO2 can be used in many fields, such as gas sensors,solar cells and transparent electrodes, is a kind of special function thin film used extremely widespread.In order to obtain the films with high transparency, excellent light performance, and electrical resistivity of the transparent conductive, we use metal salts SnCl2·2H2O,SbCl3 and CoCl2·6H2O as precusors, and prepared thin films of Sb-doped and Co-doped tin oxide on glasses by the sol-gel method. The microstructure and surface morphology of Sn2 thin filmswere investigated by XRD and AFM; The average transmissibility in visible light of SnO2 thin films were measured by the Ultraviolet-Visible Spectrophotometer. The luminescence of SnO2 thin films were measured by fluorospectrophotometer. The sheet resistance value of SnO2 thin films were measured by the DSY-5 four probes resistances reflectoscope reflector. The influences of annealing temperature and dopant amount of Sb-doped and Co-doped SnO2 thin films were discussed. The results were showm as follows:1.It was found that the microcrystalline of Sb-doped thin films and Co-doped thin films are quartet rutile structure. which are the same as SnO2. and higher temperature can be benefit to the crystallization of SnO2 crystals. Sb-doped films with good crystallinity were grown with dopant amount of 15%-20%; And the Co-doped films with best crystallinity were grown with dopant amount of 2%. But too high doping level (Sb>15%,Co>2%)will be harmful to the crystallization performance of the films. For the undoped SnO2 films, films transmittance, photoluminescence intensity and the sheet resistance increased as temperature increased and then decreased. For the Sb-doped and Co-doped SnO2 thin films with doping concentration increasing, the films'transmissibility,photoluminescence intensity and the sheet resistance with the doping concentration increased and then decreased.2. For the undoped SnO2 films, When the heat treatment temperature is 550℃, SnO2 thin films structure the most complete, transmittance reached 89% on 550nm, the relative photoluminescence intensity of the strongest peak reached 167.9, the lowest sheet resistance 2703Ω/□; when Sb-doped 15%, Transmissivity achieve the highest 91% on 550nm, the relative photoluminescence intensity of the strongest peak reached 201.1, the lowest sheet resistance of 119Ω/□; when the Co-doped 2%, the film structure integrity, surface smoothness, transmittance reached 90% on 550nm; PL relative intensity of the strongest peak reached 160.1, the lowest sheet resistance of 876Ω/□.3.Compared with Sb doped SnO2thin films and Co doped SnO2 thin films,then found out Sb-doped SnO2 Films transmittance, photoluminescence properties and electrical conductivity better than Co-doped SnO2 thin films'.