Si基ZnS纳米薄膜的化学水浴合成及其光学特性研究

发布时间：2018-05-27 06:10

  本文选题：ZnS薄膜 + 化学水浴法　； 参考：《郑州大学》2015年硕士论文

【摘要】：在诸多半导体材料中,Zn S是一种重要的禁带宽度为3.7 e V半导体材料,在光电等方面有广泛的应用。对Zn S薄膜进行掺杂和热退火处理可以明显的改善Zn S薄膜的物理、化学等性能,在掺杂方面Zn S薄膜的n型掺杂尤为重要,为以后的p-n结的制备打下基础。本文利用化学水浴法合成了多晶的Zn S薄膜和Zn S:Al3+薄膜,深入研究了样品的微结构和光学性质。主要的研究结果有:(1)当氨水作为络合剂和p H值调节剂时,光快速热处理并没有导致非晶态的Zn S薄膜的结晶,这显示硅衬底上水浴制备结晶的Zn S薄膜单采用氨水作为络合剂是不行的;随着Thermal Treatment Temperature(Trtt)的升高,Zn S薄膜颗粒有比较明显的细化趋势,颗粒尺寸分布趋于均匀,表面粗糙度趋于减小,这可能是归结于光快速热处理过程中颗粒的重新排列和生长;薄膜的吸收边随Trtt总体趋于红移,该红移可归结于薄膜的应力的变化;Trtt的升高起初增大了薄膜中的点缺陷,随后由于薄膜内部的原子重新排列,点缺陷减少。值得注意是当Trtt300℃时,与点缺陷相关的发光峰几乎消失。(2)采用三乙醇胺作为络合剂,氨水作为p H值调节剂,在重掺杂的p型Si(100)衬底上合成了Zn O薄膜而不是Zn S薄膜,这可能归咎于Zn S的水解;选用乙二胺作为络合剂,当p H值为4时,制备出了结晶质量较好的Zn S薄膜。(3)选用乙二胺作为络合剂,研究了乙二胺浓度对Zn S性质的影响。所制备的Zn S由立方相和少量的六方相组成。未加入乙二胺时,薄膜表面粗糙,出现了明显的颗粒团聚现象。随着乙二胺浓度的增加,薄膜表面趋于光滑和致密,可以看出络合剂在改善薄膜表面方面扮演着重要的角色。光学吸收边随乙二胺浓度的增加会蓝移,这归结于薄膜中应力的影响。所有样品的发射光谱均在可见光区呈现了宽的发射带,这与薄膜中的点缺陷(锌空位和硫空位)有关。(4)前驱物锌离子浓度(CZn)对Zn S薄膜性能的影响很明显。当CZn为0.25 M时,XRD谱中观测不到明显的Zn S特征衍射峰,这表明在这种浓度下很难生成Zn S薄膜,或生成的薄膜结晶性不好,呈现非晶态。随着CZn的增加,薄膜的结晶性得到明显改善。(5)本征的Zn S薄膜的电阻率为1.5×107Ωcm,当Al Cl3为1.0 mmol时,电阻率降至4.2×102Ωcm,然后又随着Al Cl3的增加而有所增大。薄膜电阻率起初的降低归结于部分Al3+对Zn2+的替代和薄膜结晶性的改善,前者会引起薄膜中自由载流子浓度的增加,而后者会提高自由载流子的迁移率。而后电阻率的增加可归咎于晶界散射的增强。
[Abstract]:ZNS is a kind of important semiconductor material with a band gap of 3.7 EV, which has been widely used in the field of photoelectricity and so on. Doping and thermal annealing of ZnS thin films can obviously improve the physical and chemical properties of ZnS films. The n-type doping of ZnS films is particularly important in doping aspect, which lays the foundation for the preparation of p-n junctions in the future. Polycrystalline ZnS and Zn S:Al3 thin films were synthesized by chemical bath method. The microstructure and optical properties of the samples were studied. The main results are as follows: (1) when ammonia is used as a complexing agent and pH value regulator, rapid photothermal treatment does not result in the crystallization of amorphous ZnS films. The results show that it is not possible to use ammonia water as complexing agent to prepare crystalline ZnS thin films on Si substrates in water bath, and the grain size distribution tends to be uniform with the increase of Thermal Treatment temperature trtt. The surface roughness tends to decrease, which may be attributed to the rearrangement and growth of the particles during the photorapid heat treatment, and the absorption edge of the film tends to redshift with the Trtt as a whole. The redshift can be attributed to the change of stress in the film. The increase of Trtt initially increases the point defect in the film, then decreases the point defect due to the rearrangement of atoms in the film. It is worth noting that, at Trtt300 鈩，

本文编号：1940769