| Transparent conductive oxide (TCO) films with high conductivity and high visibleoptical transparency are highly desired for photoelectric applications such as thin film solarcells, thin film transistors, flat-panel displays, and ultraviolet light emitting diodes. In recentyears, with the vigorous development of the organic photovoltaic devices, flexible hasbecame a new demand for transparent conductive oxide films. Amorphous oxide materials,such as indium gallium zinc oxide (IGZO), zinc indium tin oxide (ZITO), indium zinc oxide（IZO）can satisfy this requirement, while maintaining the traditional good electricalconductivity and light transmittance of transparent conductive films. However, the theory andexperiment of amorphous oxide semiconductor material research is far behind traditionalsemiconductor materials, therefore, this article has carried out the study of preparationmethods and electrical transport properties of amorphous IZO material.Considering introduction above, researches in this work list as follow:(1) Deposited IZO films by PLD under different atmosphere (O2/Ar) and differentpartial pressure (0.15-4.7Pa). The results show that films deposited in O2have amorphousstructure and carrier concentration increased with decreasing O2pressure. However, filmsdeposited in Ar have polycrystalline structure and carrier concentration increased withincreasing Ar pressure. In addition, films deposited in O2have smooth surface, but theroughness increased with increasing pressure when films deposited in Ar. The carrierscattering mechanisms in amorphous and polycrystalline IZO films were discussed in termsof carrier concentration and temperature dependent Hall effect measurements. We canconclude that the dominant scattering mechanism is defect scattering for ne~3.0×1018cm-3,then is a combination of defect and ionized impurity scatterings for ne=8.8×1019~2.0×1020cm-3. For IZO conductive films with ne>3.1×1020cm-3, grain boundary scattering seriouslylimits the electron mobility because the oxygen-deficiency during the growths makes the IZOfilms transform from amorphous to polycrystalline. All the IZO films are highly transparent(transmission>85%) at550nm, and amorphous IZO films followed Brustein-Moss effect.(2) IZO films deposited by PLD have good photoelectric property, but the cost of thismethod is high and it is difficult to deposit in large area. So it is need to find a new approachto grow IZO films to make it satisfy the need of industrial production. We tried to grow IZOfilms by sol-gel, but the films grown by this method were insulated. In order to resolve thisproblem, pulse laser with different intensity was applied to samples and the effect of laserintensity on crystallization properties, luminescent properties and electrical properties offilms was discuss. The results show that samples without pulse laser process (0mJ/cm2) were constituted of ZnO and In2O3polyphase structure, which can introduce a large of defect tocapture the free carrier, limit the electrical properties of samples and enhancephotoluminescence (PL) in visible range. However, samples with pulse laser process(60-120mJ/cm2) can improve their electrical properties, as the pulse laser has large energywich can decompose polyphase and form amorphous phase. So that, the number of defectwas reduced and the electrical properties were improved. The minimum surface resistancereached302Ω/sq and the transmission was above70%at550nm. These performances canmeet the basic needs of industrial applications. When the pulse laser intensity is above140J/cm2, samples prefer to grow followed ZnO (002), which can introduce defect again andincrease sheet resistance simultaneously. |
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