【作者】 段理；

【导师】 傅竹西；

【作者基本信息】 中国科学技术大学 ， 凝聚态物理， 2006， 博士

【摘要】 ZnO作为第三代的宽禁带半导体材料，因其在室温下约3.37eV的禁带宽度和高达60meV的激子结合能受到了广泛关注，被认为是有望取代GaN的新一代短波长光电子材料。从1996年首次报导ZnO薄膜的室温紫外发射距今已有十年，但ZnO基激光二极管、发光二极管等短波长光电器件仍未达到实用化的水平，其中一个重要原因是高质量的p型ZnO薄膜的稳定、可重复制备工艺尚未实现，此外ZnO薄膜的发光效率也有待进一步提高。 ZnO薄膜的异质外延也是非常重要的课题。采用异质外延并选取合适的基片能在很大程度上节约成本，是ZnO薄膜器件产业化的基础。Si就是这样一种价格低廉且易于光电集成的基片，但由于Si和ZnO失配严重，在Si上外延高结晶质量的ZnO薄膜是一个仍待解决的问题。 ZnO薄膜具有光电转换特性，有望成为太阳能电池材料；此外结合其宽禁带特征，也可作为紫外探测器件材料，在军事、民用方面有着广阔前景。 围绕上述背景，本论文以溅射工艺制备的ZnO薄膜为研究对象，从以下三个方面开展了工作： 首先，研究了ZnO的Ag掺杂，并观察到过量Ag掺杂导致形成的ZnO-Ag2O薄膜纳米复合结构。实验表明掺银的ZnO薄膜有转化为p型的趋势，并对ZnO本身的紫外发光有极大的增强，是一种极有潜力的掺杂方案。 其次，系统研究了利用溅射工艺在Si基片上外延ZnO薄膜过程中各参数的优化，分析了ZnO薄膜中的深能级缺陷，利用SiC、Al₂O₃等过渡层在Si基片上进行了外延高质量ZnO薄膜的尝试。结果表明两种过渡层都能有效改善Si基片上外延的ZnO薄膜的结晶质量，Al₂O₃过渡层还能显著提高ZnO薄膜的生长速率。 最后，研究了ZnO薄膜的光电转化特性及紫外响应特性，在此基础上成功制备了ZnO基紫外探测器原型器件。更多还原

【Abstract】 ZnO is a semiconductor material with a wide band-gap of 3.37eV and a high exciton binding energy of 60meV at room temperature. Recently, it was considered to be a new photo-electric material in shortwave length as GaN. In 1996, stimulated UV emission of ZnO at room temperature was reported, and ZnO as a UV laser material attracted people’s attention immediately. There are two crucial difficulties for ZnO shortwave light emitter applications need to be solved. One is that the reliable and reproducible technique to grow high quality p-type ZnO is not found yet. Another is that the intensity of UV emission from ZnO film is not strong enough.The hetero-epitaxy of ZnO film is also an important work. Si is a nice substrate because of its low cost. However, to grow higher crystal quality ZnO films on Si substrate is rather difficult because of the mismatch between ZnO and Si.ZnO is a semiconductor material with photo-voltage property. It is a potential candidate of solar cells. It also can be applied to UV detectors because of its wide band-gap.Considering these research background, the contents of the dissertation are listed as follows:Firstly, the electrical and optical properties of Ag-doped ZnO were studied. Ag-doped ZnO was found to be a potential p-type semiconductor material. Furthermore, novel enhancement of ultraviolet emission of Ag-doped ZnO was observed due to Ag₂O nanoclusters formatted during Ag doping.Secondly, the epitaxy parameters of the ZnO films on Si substrates using ratio-frequency magnetron sputtering were studied for growing higher crystal quality ZnO. The deep level centers in ZnO films on Si substrates were also studied. SiC and Al₂O₃ buffer layers were applied to prepare better ZnO films on Si substrates. The results showed that both the two type of buffer layers can improve the crystal quality of ZnO films on Si substrates. Moreover, Al₂O₃ buffer layer can increase the thickness of ZnO films.Lastly, the photo-voltage property of ZnO film was studied. ZnO films also showed a sensitive ultraviolet response because of its wide band-gap. Based on these results, primitive ZnO ultraviolet detectors was successfully prepared.更多还原