非极性ZnO薄膜及其异质结器件的制备与性能研究

发布时间：2018-04-27 03:40

  本文选题：非极性ZnO + NiO(111)/ZnO(1120)异质结　； 参考：《浙江大学》2014年硕士论文

【摘要】：外延ZnO薄膜大多数沿着c轴方向择优生长,沿着c轴方向生长的ZnO薄膜,锌原子层与氧原子层交替排列,由于缺少反演对称性,从而导致了很强的晶格自发极化效应,降低了ZnO基器件的效率。使ZnO材料沿着非极性或半极性方向生长可避免或削弱晶格极化效应造成的不良影响。另一方面,制备高质量的p型ZnO材料仍是一世界性研究难题,这极大程度上阻碍了ZnO同质pn结器件的发展。作为一种选择性方案,采用p型材料与n型ZnO制备异质结开始受到了关注。 本文采用脉冲激光沉积系统(PLD),制备了不同Li含量的LixNi1-xO薄膜、高质量的非极性ZnO薄膜、不同结构的p-NiO(111)/n-Zn0(1120)异质结和Mg0.2Ni0.8O/ZnO异质结。研究了生长参数对LixNi1-xO薄膜性能的影响、p-NiO(111)/n-ZnO(1120)异质结的性能和Mg0.2Ni0.8O/ZnO异质结的能带结构。具体工作如下： 1、在石英衬底上制备了LiXNi1-xO薄膜,研究了生长参数对制备的LixNi1-xO薄膜性能的影响,结果表明沉积压强和衬底温度对薄膜的晶体质量、光学性能、电学性能有较大影响。在350℃,5Pa的条件下制备的LixNi1-xO薄膜的综合性能较佳。 2、参考在石英衬底上制备LixNi1-xO薄膜的实验结果,我们在r面蓝宝石上制备了两种不同结构的p-NiO(111)/n-ZnO(1120)异质结,通过改变Lio.07Ni0.93O薄膜的沉积压强,并在NiO与ZnO之间插入MgZnO中间层,获得了性能较好的异质结。 3、在上述工作的基础上,制备了禁带宽度大于NiO的MgNiO薄膜。采用X射线光电子能谱法研究了Mgo.2Nio.80(111)/ZnO异质结中ZnO的生长取向对于异质结价带带阶的影响。Mgo.2Nio.80(111)/ZnO(1120)和Mgo.2Ni0.80(111)/ZnO(0002)两种异质结的价带带阶分别为1.8±O.1eV和1.4±0.1eV,导带带阶为2.4±0.1eV和2.0±0.1eV。两种异质结都呈现type-Ⅱ能带结构,两种异质结能带结构的差异主要原因是在极性ZnO中存在自发极化效应。
[Abstract]:Most of the epitaxial ZnO thin films have preferred growth along the c-axis, and the ZnO films grown along the c-axis have alternating arrangement of zinc atomic layer and oxygen atomic layer. Due to the lack of inversion symmetry, the lattice spontaneous polarization effect is very strong. The efficiency of ZnO based devices is reduced. The negative effects of lattice polarization can be avoided or weakened by the growth of ZnO materials along non-polar or semi-polar directions. On the other hand, the preparation of high quality p-type ZnO materials is still a worldwide research problem, which greatly hinders the development of ZnO homogenous pn-junction devices. As a selective scheme, the preparation of heterojunctions using p-type materials and n-type ZnO has attracted more and more attention. In this paper, LixNi1-xO thin films with different Li content, high quality nonpolar ZnO thin films, p-NiON 111 / n-Zn0N1120) heterostructures and Mg0.2Ni0.8O/ZnO heterostructures have been prepared by pulsed laser deposition system. The effects of growth parameters on the properties of LixNi1-xO thin films were investigated. The properties of p-NiO / n-ZnO (1120) heterostructures and the band structure of Mg0.2Ni0.8O/ZnO heterostructures were investigated. The specific work is as follows: 1. LiXNi1-xO thin films were prepared on quartz substrates. The effects of growth parameters on the properties of LixNi1-xO thin films were studied. The results show that the deposition pressure and substrate temperature have great influence on the crystal quality, optical properties and electrical properties of the films. The LixNi1-xO films prepared at 350 鈩，

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