【作者】 李丽；

【导师】 王万录； 方亮；

【作者基本信息】 重庆大学 ， 凝聚态物理， 2006， 硕士

【摘要】 氧化锌(ZnO)是一种具有六方纤锌矿晶体结构的宽禁带II-VI族半导体材料,由于其优良的特性,在太阳能电池、紫外探测器、声表面波器件、气敏传感器、透明电极等方面得到了广泛的应用。近年来,由于Al掺杂的ZnO薄膜(AZO)具有与ITO薄膜相比拟的光电性能(可见光区高透射率和低电阻率),又因其价格较低以及在氢等离子体中的高稳定性等优点,已经成为替代昂贵的ITO薄膜的首选材料和当前透明导电薄膜领域的研究热点之一。本文采用直流反应磁控溅射法用Zn(99.99%)掺Al(1.5%)靶制备出高质量的Al掺杂的ZnO(AZO)薄膜,用XRD、AFM、SEM、XPS和紫外可见、红外分光光度计等测试手段对沉积的薄膜进行了表征和分析。分析了AZO薄膜的导电机制,用Van der Pauw方法对样品的电学特性进行了测量。研究了退火温度和氧氩比对光电特性的影响。另外,研究了AZO薄膜的塞贝克效应和磁阻效应。实验结果表明,利用直流反应磁控溅射法制备的AZO薄膜,具有较好的晶体结构和光电特性。XRD表明,制备的薄膜为多晶,具有C轴择优取向。退火处理能使其结晶度提高。薄膜应力随着退火温度的增加而减小,随着氧氩比的增大而增大。AFM和SEM表明,样品表面较平整,粗糙度较小,且晶粒较致密。XPS分析表明:Zn元素仅是以氧化物的形式存在;Al元素含量较少;Ar+刻蚀能使AZO薄膜表面吸附的游离态氧减少。薄膜的光谱分析结果表明:薄膜样品的可见光透射率平均值均在80%以上,随着退火温度的升高,薄膜的透射率稍微增大,且薄膜光吸收边向短波方向移动。但是氧氩比的大小对薄膜的透射率影响不大。AZO薄膜在紫外有很强的吸收峰,在红外区域,其反射率可达70%。薄膜的电学性能分析结果表明, AZO薄膜的电阻率受退火温度和氧氩比的影响较大。随着退火温度的升高,电阻率减小,载流子浓度和迁移率增大。随着氧氩比的增大,电阻率增大,迁移率减小。由以上对AZO薄膜的组织结构和光电性质的研究,我们得到了用直流反应磁控溅射法制备AZO薄膜的最佳工艺条件为:氧氩比0.3/27,衬底温度200℃,工作压强5Pa,靶基距7.5cm,功率58W,退火温度400℃。在此条件下制备的AZO薄膜其透射率高达90%,电阻率可降至10-4?.cm。因此AZO薄膜具有低电阻率、高透射率和高反射率等特点,可作为透明电极用于光电器件中。AZO薄膜的塞贝克效应的结果表明:AZO薄膜具有明显的塞贝克效应,温差电动势随着温差( ?T )的增大而呈线性增大。样品的电阻越大,温差电动势率越小。更多还原

【Abstract】 ZnO is a II-VI semiconductor material with wide band-gap, which has hexagonal wurtzite structure. ZnO thin films were widely applied in solar cell, UV detector, SAW device, gas sensor and transparent electrodes et al for their excellent properties. In recent years, Al-doped ZnO(AZO)thin films has become a hot issue of transparent conductive thin films field and preferred materials instead of ITO films not only because of their comparable optical and electrical properties (high optical transparency in the visible range, low electrical resistivity) to ITO films, but also because of their lower price and higher thermal and chemical stability under the exposure to hydrogen plasma than ITO.In this paper, High quality of AZO thin films were prepared by direct current (DC) reactive magnetron sputtering using a Zn target (99.99%) containing Al of 1.5%. The films obtained were characterized and analyzed by XRD, AFM, SEM, XPS and ultraviolet-visible and infrared light spectrophotometer.The conduction mechanism has been analyzed and the electrical properties had been investigated by Van der Pauw method. It was also found that Oxygen argon (O2/Ar) ratio and annealing temperature had great influence on the optical and electrical properties. The Seebeck and magnetoresistive effects were also studied.The experimental results showed that the AZO thin films had the structural, optical and electrical properties better. It was found that the obtained films were poly-crystalline and highly orientation growth with the C-axis perpendicular to the substrate surface. The crystallinity of AZO thin films became better after annealing treatment. The film stress decreased with increasing annealing temperature, while increases with increasing oxygen argon ratio. During the inspection by AFM and SEM, we found that the surfaces morphology of samples was even and smooth,The surface roughness was small.The films were composed of some excellent columnar crystallites. The XPS results were found that Zn existed only in the oxidized state and the concentration of Al was less and the presence of loosely bound oxygen on the surface of AZO thin films was reduced after Ar+ etching.Study for optical spectra of the films indicates that the average value of the optical transmittance of the films in the visible region exceeds 80%. With the annealing temperature increasing, the average optical transmittance increases and the absorption edge of the transmission curve of the films moves toward short wavelength. But with更多还原