Reghioua Imène, Fanetti Mattia, Girard Sylvain, Di Francesca Diego, Agnello Simonpietro, Martin-Samos Layla, Cannas Marco, Valant Matjaz, Raine Melanie, Gaillardin Marc, Richard Nicolas, Paillet Philippe, Boukenter Aziz, Ouerdane Youcef, Alessi Antonino
Univ Lyon, UJM-Saint-Etienne, CNRS, Graduate School Optics Institute, Laboratoire Hubert Curien UMR 5516, F-42023, Saint-Etienne, France.
Materials Research Laboratory, University of Nova Gorica, Vipavska 11c 5270-Ajdovscina, Slovenija.
Beilstein J Nanotechnol. 2019 Jan 16;10:211-221. doi: 10.3762/bjnano.10.19. eCollection 2019.
We report an experimental study demonstrating the feasibility to produce both pure and Ge-doped silica nanoparticles (size ranging from tens up to hundreds of nanometers) using nanosecond pulsed KrF laser ablation of bulk glass. In particular, pure silica nanoparticles were produced using a laser pulse energy of 400 mJ on pure silica, whereas Ge-doped nanoparticles were obtained using 33 and 165 mJ per pulse on germanosilicate glass. The difference in the required energy is attributed to the Ge doping, which modifies the optical properties of the silica by facilitating energy absorption processes such as multiphoton absorption or by introducing absorbing point defects. Defect generation in bulk pure silica before nanoparticle production starts is also suggested by our results. Regarding the Ge-doped samples, scanning electron microscopy (SEM) and cathodoluminescence (CL) investigations revealed a good correspondence between the morphology of the generated particles and their emission signal due to the germanium lone pair center (GLPC), regardless of the energy per pulse used for their production. This suggests a reasonable homogeneity of the emission features of the samples. Similarly, energy dispersive X-ray spectroscopy (EDX) data showed that the O, Ge and Si signals qualitatively correspond to the particle morphology, suggesting a generally uniform chemical composition of the Ge-doped samples. No significant CL signal could be detected in pure silica nanoparticles, evidencing the positive impact of Ge for the development of intrinsically emitting nanoparticles. Transmission electron microscope (TEM) data suggested that the Ge-doped silica nanoparticles are amorphous. SEM and TEM data evidenced that the produced nanoparticles tend to be slightly more spherical in shape for a higher energy per pulse. Scanning transmission electron microscope (STEM) data have shown that, regardless of size and applied energy per pulse, in each nanoparticle, some inhomogeneity is present in the form of brighter (i.e., more dense) features of a few nanometers.
我们报告了一项实验研究，该研究证明了使用纳秒脉冲KrF激光烧蚀块状玻璃来制备纯二氧化硅纳米颗粒和锗掺杂二氧化硅纳米颗粒（尺寸范围从几十到几百纳米）的可行性。具体而言，在纯二氧化硅上使用400 mJ的激光脉冲能量制备了纯二氧化硅纳米颗粒，而在锗硅酸盐玻璃上使用每脉冲33 mJ和165 mJ的能量获得了锗掺杂纳米颗粒。所需能量的差异归因于锗掺杂，它通过促进多光子吸收等能量吸收过程或引入吸收性点缺陷来改变二氧化硅的光学性质。我们的结果还表明在纳米颗粒生产开始之前块状纯二氧化硅中会产生缺陷。对于锗掺杂样品，扫描电子显微镜（SEM）和阴极发光（CL）研究表明，无论用于其生产的每脉冲能量如何，所生成颗粒的形态与其由于锗孤对中心（GLPC）产生的发射信号之间都有良好的对应关系。这表明样品的发射特征具有合理的均匀性。同样，能量色散X射线光谱（EDX）数据表明，O、Ge和Si信号在质量上与颗粒形态相对应，表明锗掺杂样品的化学成分总体上是均匀的。在纯二氧化硅纳米颗粒中未检测到明显 的CL信号，这证明了锗对本征发光纳米颗粒发展的积极影响。透射电子显微镜（TEM）数据表明锗掺杂二氧化硅纳米颗粒是无定形的。SEM和TEM数据证明，对于每脉冲更高的能量，所产生的纳米颗粒形状往往更接近球形。扫描透射电子显微镜（STEM）数据表明，无论尺寸和每脉冲施加的能量如何，在每个纳米颗粒中，都存在一些几纳米的更亮（即更密集）特征形式的不均匀性。
