铽离子掺杂碳氧化硅薄膜的制备与发光特性研究

发布时间：2018-06-15 06:28

  本文选题：硅基发光 + 碳氧化硅薄膜　； 参考：《太原理工大学》2017年硕士论文

【摘要】：近几十年来,由于硅具有优良的电学和机械等性能且在地球上储量丰富,硅材料已被广泛关注。但由于单晶硅是间接带隙半导体,电子跃迁发出光子,需要吸收或发射一个声子,这比电子直接跃迁发出光子几率小得多,这使得单晶硅发光微弱。因此设计高效、稳定的硅基发光材料是光电子技术中的关键问题。其中稀土掺杂硅基发光材料可以很好的改善硅基发光效率。因为稀土材料发光性能优良,其f-f跃迁的电子能级丰富、光谱峰形尖锐、颜色纯度高,且稀土发光受外界影响小。此外,+3价的稀土离子,每一电子层中都含有未成对的电子,跃迁时释放光子,适合掺杂到发光材料中。因此,硅基薄膜中掺杂稀土材料是实现硅基发光的一条重要途径。本文将稀土离子——铽掺杂到母体材料SiC_xO_y薄膜中,通过改变薄膜中碳元素的含量以及对样品进行不同温度的退火,从而实现铽离子的最优发光,并分析其发光机制。首先,研究母体材料SiC_xO_y薄膜中氧含量对薄膜发光的影响机制。采用高频等离子体增强化学气相沉积技术(VHF-PECVD)在250℃下制备一系列非晶SiC_xO_y薄膜。改变薄膜中氧组分的含量,氧组分的变化会影响SiC_xO_y薄膜发光性质和结构。通过光致发光光谱(PL)研究发现,随着薄膜中氧组分的增加,其发光峰位由橙红光逐渐向蓝光移动,肉眼可见较强的发射光。荧光瞬态谱分析表明,薄膜的光子寿命在纳秒量级。综合观察薄膜的XPS、FTIR光谱以及Raman谱,对薄膜的相结构和化学键合进行表征,我们分析SiC_xO_y薄膜的可调光发射机制。之后,研究铽掺杂SiC_xO_y薄膜中碳含量和退火温度对铽离子发光的影响机制。采用磁控溅射技术在250℃下制备一系列SiC_xO_y:Tb薄膜。因为薄膜中适量的碳可以促进形成纳米硅团簇,纳米硅团簇可以作为激子介导激发铽离子发光。因此,当薄膜中的碳适量时,以纳米硅团簇激发铽离子发光为主,铽离子的绿色发光增强。然而继续增加薄膜中的碳含量时,铽离子的发光强度反而减弱。这是由于薄膜中碳含量再增加时,以氧缺陷激发铽离子发光为主,但是纳米硅团簇激子激发效果强于氧缺陷激子激发效果。因此,当氧缺陷激发为主时,铽离子发光减弱。此外,通过不同退火温度之后的SiC_xO_y:Tb薄膜,铽离子的绿色发光均有增强。因此,碳含量和退火温度对薄膜中铽离子的发光均有较大的影响。本文对不同碳含量以及不同退火温度的SiC_xO_y:Tb薄膜的微结构进行表征,分析了铽离子发光增强机制且找到铽离子最优发光条件。
[Abstract]:In recent decades, silicon has attracted much attention because of its excellent electrical and mechanical properties and abundant reserves on the earth. However, since the single crystal silicon is an indirect band gap semiconductor, the electron transition emits photons, which requires the absorption or emission of a phonon, which is much less likely than the direct electron transition, which makes the single crystal silicon weak in luminescence. Therefore, the design of high-efficiency and stable silicon-based luminescent materials is a key problem in optoelectronic technology. Among them, rare earth doped Si-based luminescent materials can improve the Si-based luminescence efficiency. Because of the excellent luminescence properties of rare earth materials, the f-f transition has rich electronic energy levels, sharp spectral peaks, high color purity, and rare earth luminescence is less affected by the outside world. In addition, three valence rare earth ions, each of which contains unpaired electrons, release photons during transition and are suitable for doping into luminescent materials. Therefore, doping rare earth materials in Si-based films is an important way to realize Si-based luminescence. In this paper, rare earth ion -terbium is doped into the SiCxO _ y film. By changing the content of carbon in the film and annealing the sample at different temperatures, the optimum luminescence of terbium ion is realized and its luminescence mechanism is analyzed. Firstly, the effect of oxygen content on the luminescence of sic _ s _ XO _ y thin films is studied. A series of amorphous sic _ XO _ XO _ y thin films were prepared by high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) at 250 鈩，

本文编号：2021040