【作者】 张瀚铭；

【导师】 方庆清；

【作者基本信息】 安徽大学 ， 材料学， 2012， 硕士

【摘要】 ZnO是一种常见的半导体材料,可以较为容易的产生光致发光或者受激辐射,具有很好的应用前景,有着广泛的应用价值,ZnO单晶可以相对容易的生长,在可见光谱中具有较小的光灵敏度和高透明度以及和玻璃、塑料相兼容的温度,对环境的影响和毒性也低于其他大多数半导体,且成本低廉,使得ZnO作为透明导电薄膜具有很强的竞争力。通过在ZnO中掺杂可以有效调节ZnO的导电性能和光学性能,有利于薄膜的性能优化。本文采用激光脉冲沉积方法(Pulsed Laser Deposition PLD)制备掺杂ZnO薄膜,选取Si02及Si作为样品的衬底。文章研究了不同元素及含量对ZnO薄膜的结构性能、光学性能及电学性能的影响及改性研究,主要研究内容如下：1、本文采用的掺杂手段为脉冲激光沉积法沉积扩散掺杂,掺杂样品均呈现出单一的(002)方向的衍射峰,具有良好的择优方向的生长,掺杂进入了ZnO薄膜的晶格,薄膜的纤锌矿的结构未发生改变。2、研究了Al掺杂含量对ZnO薄膜的影响。Al的掺入使得晶面间距差别较小,掺杂没有明显改变晶格结构。薄膜的透光性降低,薄膜带隙变宽。掺杂导致样品载流子浓度升高,但在Hall迁移率的共同作用之下,样品的电阻率略降低。3、我们在上述结论条件下继续深入研究了Co/Cu掺杂和ZAO薄膜的关系。样品薄膜均呈沿(002)方向择优生长。Co掺杂会影响样品的可见光的范围内光透过率,对ZAO薄膜的光学带隙变化影响较小。Cu掺杂对样品的光透过率影响较小,但会使样品的吸收边向低能量方向发生移动。Cu掺杂较Co掺杂对载流子浓度贡献大,我们认为这是由于在相同条件下Cu比Co更容易填充间隙并提供电子。掺杂样品的性能指数低于未掺杂样品,Cu掺杂相比Co掺杂性能指数优异。4、最后我们研究Co和Cu共掺ZAO薄膜。我们认为薄膜中存在着VZn缺陷,Zni缺陷,单电离的VZn-缺陷及一价的O空位。能带间隙因掺杂而被展宽,紫外发光增强,锌空位随掺杂数量增多。载流子浓度先增加而后减少。薄膜Hall迁移率与之相反,使得样品的电阻率未发生明显的变化。掺杂减弱了样品的室温铁磁性,正是由于Cu的加入占据了相邻阳离子的位置,使得阳离子之间的双交换作用被打断,减弱了样品的原有磁性。更多还原

【Abstract】 ZnO is a semiconductor with a wide band gap (3.36eV) and large exciton binding energy (60meV). It can be relatively easy to produce photoluminescence or stimulated radiation. It has a wide range of value. The growth of ZnO single crystal is relatively easy, and ZnO has a smaller light sensitivity and a high degree of transparency. It also has low cost and the inflence on the environment and toxicity is also lower than most other semiconductors. There are all make the ZnO has a strongly practicable. By doping can effectively regulate the conductivity and optical properties of ZnO, which is conducive to the performance optimization of the film.In this paper, the pulsed laser deposition (PLD) is used for ZnO thin films on SiO2substrate. The doped films all have good c-axis orientation and different optical and electrical properties. The main contents are as follows:1、The films deposited on single-crystal SiO2substrates are prepared by pulsed laser deposition (PLD). A strong peak growth along the (002) direction at34.4°in the films is attributed to the wurtzite structure, The films have good crystallization quality. The ion into the lattice of ZnO thin films, and the structure of ZnO is not change.2、We studied the influence of Al doped into ZnO thin films. The sizes of the crystals with Al-doped are gradually growth, the film easier to form larger particles. The doping did not change the lattice of structure, and the less impact on the crystal spacing. the light transmittance of the films are reduced with doping Al. Films band gap narrowed with increasing Al. under the effect of the Hall mobility and carrier concentration, the resistivity of the samples decreased with increasing Al doping content.3、We continue study of Co/Cu doping ZAO thin film. Co doping will affect the transmittance of the sample, the less impact on the change of the optical band gap of ZAO films. Cu-doped sample of the transmission rate is less affected, but doped will move absorption edge of the sample to the short wavelength. Cu doping carrier concentration much higher than Co doping, the doped samples performance index are lower than the un-doped samples, and the maximum is the Cu doping of the samples.4、We have studied the Co and Cu doped ZAO films. We believe that the existence of defects Vzn, Zn;, the single ionization Vzn defects and a price of O vacancies in the film. Band gap broadening and the free exciton emission enhanced with doping. The carrier concentration first increases and then decreases, Hall mobility showed the opposite trend, the resistivity of the sample is not changed significantly.更多还原