Institute for Solid State Physics, University of Jena, Max-Wien-Platz 1, Jena, 07743, Germany.
Nanotechnology. 2019 Mar 1;30(9):095201. doi: 10.1088/1361-6528/aaf82c. Epub 2018 Dec 12.
Tunable nanoscale light emitters are essential to accomplish future multifunctional optoelectronic nano-devices. Here, we present an approach for achieving red electroluminescence from single ZnO nanowires (NWs) implanted with europium ions. The electroluminescence is emitted mainly from the end facets of ZnO NWs at room temperature under the application of an AC voltage. The corresponding electroluminescence spectrum is attributed to the radiative intrashell transitions of the Eu ions, while contributions from near band edge or deep level emission of the ZnO remain absent. The total intensity of the electroluminescence is linearly proportional to the length of the NWs, whereas there is no clear correlation with other morphology factors of the NW based device such as the diameter. Furthermore, the underlying excitation mechanism of the electroluminescence is proposed as direct-impact excitation of Eu ions by hot electrons in the ZnO NWs.
可调谐纳米级发光体对于实现未来多功能光电纳米器件至关重要。在这里，我们提出了一种在掺铕的氧化锌纳米线（NWs）中实现红光电致发光的方法。在室温下，通过施加交流电压，电致发光主要从 ZnO NWs 的端面对发射。相应的电致发光光谱归因于 Eu 离子的壳层内辐射跃迁，而 ZnO 的近带边或深能级发射的贡献则不存在。电致发光的总强度与 NWs 的长度呈线性比例关系，而与 NW 器件的其他形态因素（如直径）之间没有明显的相关性。此外，提出了电致发光的潜在激发机制，即 ZnO NWs 中的热电子对 Eu 离子的直接碰撞激发。
