用稀土掺杂增强硅基氧化锌薄膜带边发光的研究

Although zinc oxide nanocrystals (nano-ZnO) thin films are of significantly fundamental and potential applications in many fields including ultraviolet (UV) lasers, photo-detectors, Si-based light emission et al., light emission from the band edge of ZnO still need to be enhanced greatly to meet the enormous challenge. In recent years, we found that the band edge emissions from Si-based nano-ZnO films after high temperatures (1000-1100℃) annealing, can be enhanced by 1-2 orders of magnitude by doping rare earths (Res) in the nano-ZnO films. However, the reasons for the great UV enhancements and the inert excitation mechanism are still not very clear. In this project, we will prepare the nano-ZnO films with different technologies, and study the bandedge emission properties of the films after various Res (such as Eu, Ce, Tb and Yb) doping and high temperatures annealing. We will propose the influence mechanism in/between the Res doping-microstructure-UV emission after a great deal of experimental examinations, to reveal the strong enhancement of UV emission for the ZnO films induced by Res doping. We will further study the passivation decoration to the surface of ZnO film, and seek new path to enhance the UV emissions by using energy coupling between nano-metal surface plasmon and nano-ZnO. Through the project investigation, we hope to optimize the preparation technology for the nano-ZnO thin films, and realize its bandedge electroluminescence, to establish a good basis for the wide applications of nano-ZnO in UV photonics and Si-based photonics.

纳米氧化锌（ZnO）薄膜在紫外激光器、探测器、硅基发光等许多方面都具有重大的潜在的应用价值，但其带边发光强度的提高仍有巨大的挑战性。近年来，我们发现在高温退火条件下稀土掺杂的硅基ZnO薄膜，其帶边发光要比不掺杂的ZnO薄膜极大增强，增强的原因和内在激发机制尚不十分清楚。本项目旨在研制几种不同工艺路线制备的纳米ZnO薄膜，研究在稀土（Eu、Ce、Tb、Yb）掺杂和高温退火后的帶边发光性能。通过大量的实验验证，探索优化的稀土掺杂薄膜的制备工艺，提出稀土掺杂-微观结构-紫外发光之间的影响机制，揭示掺杂导致ZnO薄膜带边发光增强的机理。我们进一步通过纳米金属颗粒对ZnO薄膜表面进行钝化修饰，利用表面等离激元与纳米ZnO间的能量耦合寻找增强紫外发射的新途径。通过本项目的研究，优化纳米ZnO薄膜的制备工艺，并实现基于稀土掺杂的ZnO薄膜带边电致发光，为其在紫外光电子学和硅基光电子学方面的应用奠定基础。

增强纳米氧化锌（ZnO）薄膜的紫外发光，是实现薄膜在紫外激光器、紫外探测器、气体传感器等光电子学方面许多应用的关键之一。本项目围绕利用稀土掺杂对ZnO薄膜结构和紫外发光的调控，开展了下述研究工作：（1）研究了高温退火条件下，稀土（Ce、Eu、Tb、Yb）掺杂浓度对ZnO薄膜结构和帶边发光性能的影响，找到了各稀土在ZnO薄膜中合适的掺杂浓度；通过大量的实验验证，得到了优化的稀土掺杂薄膜的制备工艺，揭示了稀土掺杂-微观结构-紫外发光之间的影响机制，以及掺杂导致ZnO薄膜带边发光增强的机理。（2）在此基础上，研究了利用等离激元和微球阵列进一步增强ZnO薄膜紫外发光性能的途径。我们发现在超薄Al层（~ 2.0 nm）和 SiO2微球（~ 5.0 micro）协同作用下，稀土掺杂的ZnO薄膜紫外发光，能在此前1-2个数量级发光增强的基础上再增强30倍左右，基本实现了我们项目预期的紫外发光增强目标。（3）我们深入研究了MgZnO薄膜的制备工艺和发光性质，并以此为载流子注入层准备实现基于ZnO薄膜的近带边电致发光。通过本项目的研究，我们揭示了稀土掺杂增强ZnO薄膜紫外发光的机制，优化了纳米ZnO薄膜的制备工艺，极大提高了ZnO薄膜的紫外发光性能，并为实现基于稀土掺杂ZnO薄膜带边电致发光奠定了基础。这项研究有助于进一步拓展ZnO薄膜在紫外光电子学和硅基光电子学方面的应用。