Amorphous IZO Transparent Conductive Films Prepared By Sol-gel Method And The Effects Of UV Laser Irradiation On Their Electrical Properties

Transparent conductive oxide(TCO)films with high conductivity and transmittance in visual spectral region were highly desirable for photoelectric devices,such as thin film solar cells,thin film transistors,flat-panel displays and ultraviolet light emitting diodes.With the vigorous development of the organic photoelectric devices,novel flexible TCOs are attracting more and more attentions.Due to their high electrical conductivity,amorphous oxide semiconductor materials had become one of the hotspots in the flexible transparent conductive materials.Ternary or quaternary alloyed metal oxides like indium zinc oxide(IZO),indium gallium zinc oxide(IGZO)and zinc indium tin oxide(ITZO)were regarded as promising candidates to replace the traditionally brittle TCOs as transparent electrodes.However,the theoretical and experimental researches on amorphous oxide semiconductor materials were far behind the traditional semiconductor materials.In the thesis,we studied the optical and electrical properties amorphous IZO materials prepared by modified sol-gel method.The main contents were as follows:(1)We deposited IZO films by sol-gel method under different In/Zn molecular ratio and different annealing temperature to optimize of amorphous IZO films growth conditions.The results show that when the In:Zn ratio was 50:50 and the annealing temperature was 500 oC,the amorphous IZO films were obtained got because of the crystal structure mismatching between ZnO and In2O3.The lowest electrical resistivity is 2.5×10-2?cm with the transmittance of 92% at 550 nm.(2)UV laser irradiation treatments were carried out on the amorphous IZO films prepared by sol-gel.We found that the working mechanism of UV laser irradiation is different for IZO films annealed at different temperatures: when the annealing temperature was lower than 500?,UV irradiation can efficiently remove a lot of residual organics in amorphous IZO films and increase the carrier concentration and mobility;when the annealing temperature was higher than 500?,most residual organics were removed.But after UV irradiation the resistivity still fell down by one order of magnitude.This phenomenon could be explained as that the UV irradiation was able to effectively reduce the concentration of absorbed oxygen which can capture and scatter electrons and increased the concentration and mobility of carriers.In this regard,the electrical properties of amorphous IZO films were improved.To sum up,UV laser irradiation could effectively reduce the annealing temperature needed for preparing IZO based transparent conductive films by traditional sol-gel method.Our research could be a guidance and reference for preparing transparent conductive films viatraditional sol-gel method at low temperatures.