Ge-Sb-Se薄膜的制备及光致结构变化研究

发布时间：2018-07-24 08:40

【摘要】：在非晶硫系材料中,光致结构变化是一种十分重要的现象,而Ge-Sb-Se体系薄膜内部结构中存在着各种缺陷以及特殊键,极其容易在光照条件下发生键的断裂与重组,这会引起薄膜性能的改变。又因为此类材料具有较宽的红外透过窗口、较低的光学损耗、较快的光学响应时间、较高的折射率以及较好的热稳定性等优良特性,使其在静电复印、非线性光学、全息存储等现代集成光电子学器件领域呈现出巨大的应用价值。本文我们主要研究了Ge-Se和Ge-Sb-Se非晶硫系薄膜的透过率变化,以及这些薄膜在近带隙光照射下的光致暗化和光致漂白现象。使用动力学拟合公式得到Ge-Sb-Se薄膜的动力学参数,探究光致变化现象与组分及平均配位数的关系,使用拉曼光谱研究这种光致变化与薄膜内部结构变化的关系。主要的研究结果如下:1.使用磁控溅射法在GeSe_2和GeSe_4组分中掺杂Sb元素后的薄膜保持着良好的非晶特性以及良好的透过率,但是透过光谱均发生了红移,也就是吸收截止边向长波方向移动,且当Sb含量过大,透过率明显降低。2.由GeSe_2与Sb靶材制备的薄膜在655 nm泵浦激光照射下同时出现了快速光致暗化与缓慢光致漂白两种相反现象,且最终饱和至某一状态。薄膜组分从Se缺到Se富,薄膜的光致特性从光致暗化过渡到光致漂白,中间存在一个中间光稳定态,而此时状态的平均配位数约为2.69,此值接近硫系薄膜二维结构过渡到三维结构的平均配位数(2.67)。3.由GeSe_4与Sb靶材制备的薄膜在655 nm泵浦激光照射下同时出现了光致暗化与光致漂白两种相反现象,但都为光致暗化薄膜。且随着Ge含量的降低光致漂白程度减弱,最终不存在光致漂白现象。4.GeSe_2与GeSe_4均为光致漂白薄膜,但在GeSe_2薄膜中不存在光致暗化现象,其光致漂白程度高于GeSe_4薄膜,其中GeSe_2中的Ge含量相对较高。5.通过拉曼光谱,我们可以发现薄膜的光致暗化主要是由于Ge-Ge同极键和Sb-Se键的增加以及Ge-Se键的减少;相反的光致漂白主要是由于Ge-Ge和Sb-Sb同极键的减少,以及共顶角GeSe_4四面体转化为共边GeSe_4四面体。
[Abstract]:The photoinduced structural change is a very important phenomenon in amorphous sulfur materials. However, there are various defects and special bonds in the internal structure of Ge-Sb-Se films. It is very easy to break and recombine the bonds under illumination. This will result in a change in the properties of the film. Because of its wide infrared transmission window, lower optical loss, faster optical response time, higher refractive index and better thermal stability, this kind of material can be used in electrostatic photocopying and nonlinear optics. Holographic storage and other modern integrated optoelectronic devices show great application value. In this paper, we have studied the change of transmittance of Ge-Se and Ge-Sb-Se amorphous sulfur films, and the photoluminescence and photobleaching of these films under near-band gap light irradiation. The kinetic parameters of Ge-Sb-Se thin films were obtained by using the kinetic fitting formula. The relationship between the photoinduced changes and the composition and the average coordination number was investigated. The relationship between the photoinduced changes and the internal structure changes of the films was studied by Raman spectroscopy. The main findings are as follows: 1: 1. The thin films doped with SB in GeSe_2 and GeSe_4 by magnetron sputtering have good amorphous properties and good transmittance, but the transmission spectra are all red-shifted, that is, the absorption cutoff edge moves towards the long wave direction. When SB content is too high, the transmittance decreases obviously. The films prepared by GeSe_2 and SB targets were irradiated by 655nm laser at the same time, both rapid photo-dimming and slow photobleaching appeared, and finally saturated to a certain state. The composition of the film is from se deficiency to se rich, the photo-induced properties of the film transition from photo-dimming to photobleaching, and there is an intermediate light stable state in the film. The average coordination number is about 2.69, which is close to the average coordination number (2.67). The films prepared by GeSe_4 and SB targets have two opposite phenomena of photo-dimming and photobleaching under 655nm pumped laser irradiation, but they are both photo-darkening films. With the decrease of GE content, there was no photobleaching phenomenon. 4. Both GeSe2 and GeSe_4 were photobleaching films. However, there was no photobleaching in GeSe_2 films, and the photobleaching degree was higher than that in GeSe_4 films. The content of GE in GeSe_2 is relatively high. By Raman spectroscopy, we can find that the photo-darkening of the films is mainly due to the increase of Ge-Ge and Sb-Se bonds and the decrease of Ge-Se bonds, whereas the photobleaching is mainly due to the decrease of Ge-Ge and Sb-Sb copolar bonds. The coparietal GeSe_4 tetrahedron is transformed into cosided GeSe_4 tetrahedron.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O484

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