Thesis Advisor王丹
Degree Grantor中国科学院大学
Degree Discipline化学工程

紫外线对人类的生产生活以及生物的生长发育等都有着巨大的影响,近年来开发研制高探测性能的紫外光电探测器越来越受到科研界及工业界的广泛关注。SnO2半导体具有较大的禁带宽度,以其作为紫外光电探测材料可以较好地避免可见光的干扰,因此被视为是一种理想的紫外光电探测器材料。然而传统的SnO2光电探测器存在光吸收利用率较低的问题,因而其光电响应度和探测度受到了较大的影响。中空多壳层结构(HoMSs)具有丰富的孔结构,有序的壳层排布和多级次的空腔结构,能将光限域在多壳层空腔之中,从而增加光的反射与散射促进材料对光的吸收和利用。纳米空心球结构对入射光形成封闭的回路,光能够沿着球壳内壁进行多次反射散射,避免光线直接穿过球体或是在球体表面吸收和反射,从而可以提高材料对光的吸收效率,这对宽带隙半导体材料尤为重要。因此,SnO2 HoMSs是一种理想的光电探测材料,有望解决传统SnO2光电探测器光电响应度和探测度较低的问题。本文的主要的研究结果分为如下三个方面:(1)利用次序模板法,采用碱化处理过的碳微球做为模板,通过对前驱体金属离子溶液的浓度、吸附时间以及煅烧程序的调控制备出不同壳层数目的单、双、三、四壳层SnO2 HoMSs。(2)利用丝网印刷法将单、双、三、四壳层SnO2 HoMSs制备为薄膜均匀铺设在SiO2/Si基底上,并通过真空热蒸镀的方法将Cr/Au电极均匀沉积在HoMSs薄膜表面得到光电探测器。研究发现,随着壳层数目的增多,SnO2 HoMSs光电探测器其探测性能不断提升,其中四壳层SnO2 HoMSs光电探测器的光电探测性能最佳,在入射波长260 nm下电压5 V时其光电流达到231.0 μA,光电响应度R约1.01 × 104 A/W,外量子效率EQE约5.23 × 106%,探测度D约3.83 × 1012 Jones。其光电响应度、外量子效率、探测度为SnO2纳米粒子光电探测器的35.3, 38.4和33.9倍。SnO2 HoMSs光电探测器展现出优异的光电探测性能。(3)光电探测器在轨运行期间会遭遇各种高能宇宙射线,我们研究了单、双、三、四壳层SnO2 HoMSs以及纳米粒子光电探测器在不同辐射剂量γ射线下的抗辐射性能。实验结果表明,随着辐射剂量的增加,探测器的光电流、光电响应度和外量子效率以及探测度都发生不同程度的衰减,但经过辐照后的单、双、三、四壳层SnO2 HoMSs以及SnO2纳米粒子光电探测器,其光电流、响应度、外量子效率以及探测度的大小依然是四壳层SnO2 HoMSs光电探测器最高。当γ射线在辐射剂量为100 krad时,四壳层SnO2 HoMSs光电探测器其光电响应度2.59 × 103 A/W,而SnO2纳米粒子光电探测器其光电响应度仅仅衰减至22.3 A/W。具有中空多壳层结构的光电探测材料具有优异的抗辐射性能。中空多壳层结构为我们设计制备具有优异光电参数和抗辐射性能的新型光电探测器奠定了良好的基础。;Ultraviolet light is significant concerned because it tremendous impact on people's daily life, industrial and agricultural production, herein, the fabrication of a UV photodetector with excellent photoelectric performance have attracted a broad attention. SnO2 has been reported as an ideal material for the detection of ultraviolet light due to its wide band gap accompanying with the transparency in visible spectral area. However, the responsivity and detectivity of reported SnO2 photodetectors are not satisfy due to the poor light utilization, which is a crucial part of photoelectric conversion process. Hollow multi-shelled structures (HoMSs) based materials have their natural advantages in light absorption because these multi shells can trap the light in their internal cavities. Circular nanospheres form a closed route to the incident light source and enable light to propagate along the spherical shells instead of directly cross over the spheres, which can improve the near-surface absorption efficiency thus improving the ability of light harness process, which is especially significant to a wide bandgap nanomaterial. Accordingly, a great option of UV sensitive materials SnO2 with a suitable structure HoMSs are hopeful to solve the weakness in responsivity and detectivity of traditional SnO2 photodetectors. Herein, the main research results of this paper can be divided into the following three aspects:(1) SnO2 HoMSs were synthesized by using the sequential templating approach with the template of alkali-treated carbonaceous microspheres (ATCMS), and the shell numbers of SnO2 HoMSs can be regulated by the adsorption of Sn4+ ions concentrated in the center of the ATCMS.(2) The as-assembled SnO2 HoMSs were deposited on Si/SiO2 substrate by screen printing technique. The Cr/Au (200 nm/800 nm) electrodes were deposited on the surface of SnO2 HoMSs film by thermal evaporation. 4S-SnO2 HoMSs photodetector exhibit the strongest light capture capability, a well photoelectric conversion ability accompanied by an R of 1.01×104 AW-1, EQE of 5.23×106%, and high D* of 3.83×1012 Jones which were enhanced by 35.3, 38.4 and 33.9 times, respectively compared to those of SnO2 NPs device at 260 nm irradiation. (3) 1S-, 2S-, 3S-, 4S-SnO2 HoMSs and SnO2 NPs photodetectors were irradiated by different doses of gamma rays from 0 to 100 krad. With the increasing of irradiation dose, the photocurrent, R and D* of the photodetectors begin to attenuate. While the photoelectric parameters of HoMSs devices are all the higher than those of SnO2 NP one under all radiation doses. For example, when the radiation dose reaching to 100 krad, the R value of the SnO2 NPs device has decreased to 22.3 A/W, while it is still over 103 A/W for 4S-SnO2 HoMSs device. Here, we can conclude that the structure of HoMSs has shown its great advantages in the design of radiation-resistant and highly sensitive photodetectors.Key Words: SnO2, HoMSs, photodetector, anti-irradiation 

Document Type学位论文
Recommended Citation
GB/T 7714
李萌. 中空多壳层结构SnO2在紫外光电探测器中的应用[D]. 中国科学院大学,2019.
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