纯相黄铁矿纳米单晶的制备及其光电性能的研究

发布时间：2018-05-18 20:31

  本文选题：水热法 + 黄铁矿　； 参考：《电子科技大学》2015年硕士论文

【摘要】：黄铁矿FeS2作为一种储量丰富、无毒的化合物半导材料,具备理想的禁带宽度(0.95 eV),高光吸收系数(~105 cm-1,hν1.3 eV)和迁移率(~360 cm2V-1s-1)等优异光电性能,因而在太阳能电池与光电探测领域备受关注。本文采用了低成本、绿色环保和简单可控的水热法,以FeCl2·4H2O与S粉为主要原料,明胶为表面活性剂实现了纯相黄铁矿纳米单晶的快速合成,并利用XRD、SEM、HRTEM、EDS、UV-vis等方法对黄铁矿进行了性能表征。然后,进一步研究了不同反应时间和S/Fe摩尔比对纳米单晶的成分、结构、形貌及缺陷的影响。最后,通过制备简易的光电探测器对其光电性能进行了分析。本文主要得到以下主要研究成果:1)水热法制备黄铁矿纳米单晶实验在S/Fe=3.75/1,t=48 h,pH=12.3,T=200℃的条件下得到黄铁矿纳米单晶,无白铁矿、FexO1-x等杂质;晶格常数a=0.5417 nm,尺寸分布在20~40 nm;主要呈球状、立方状和多面体,活性剂的分解导致晶粒间团聚比较严重。2)黄铁矿纳米单晶合成工艺的优化在S/Fe=2.5/1不同反应时间(12、24、48 h)条件下,时间越短,FexO1-x越多,形貌多呈球状,尺寸较小且分布均匀,无团聚现象;时间越长,黄铁矿增加,形貌呈球状、立方体等,尺寸变大,分布范围更大,出现团聚现象。在反应时间为24 h、不同S/Fe摩尔比(1/1.5、1/0.75、2.5/1)的条件下,摩尔比越小,反而越有利于黄铁矿的生长,形貌多为球状,尺寸较小且分布均匀,无团聚现象;摩尔比增加,黄矿铁先减弱后增强,结晶程度先降低后上升,晶粒平均尺寸变大,分布范围变大,有较轻团聚现象。在反应时间为48 h、不同S/Fe摩尔比(2.5/1、3/1、3.75/1)的条件下,S/Fe摩尔比越高,黄铁矿越纯,并在S/Fe=3.75/1条件下获得纯相黄铁矿纳米单晶,形貌从球状向立方体与不规则的多面体过渡,晶粒的团聚现象减弱,但尺寸明显变大,分布区间也较大。3)黄铁矿纳米单晶的光电性能通过光刻工艺、电子束蒸发与聚焦离子束刻蚀等技术制备简易的光电探测原型器件,随后在器件上利用滴涂技术与高温退火制备致密且厚度均匀的薄膜,在光照条件下测得电流密度为1~102 mA●cm-2;由于量子尺寸效应等因素造成光吸收蓝移,通过UV-vis光吸收谱计算出禁带宽度Eg=1.53 eV,高于理论值。
[Abstract]:As a kind of abundant and nontoxic compound semiconductors, pyrite FeS2 has excellent optoelectronic properties, such as ideal bandgap 0.95 EV, high light absorption coefficient 105cm-1h v 1.3 EV) and mobility of 360cm2V-1s-1). As a result, solar cells and photoelectric detection have attracted much attention. In this paper, the rapid synthesis of pure pyrite nanocrystalline was realized by using FeCl2 4H2O and S powder as main raw materials and gelatin as surfactant by using low cost, green environmental protection and simple and controllable hydrothermal method. The properties of pyrite were characterized by the methods of XRDX SEMU HRTEMU EDS- UV-vis and so on. Then, the effects of different reaction time and molar ratio of S/Fe on the composition, structure, morphology and defects of nanocrystalline were studied. Finally, the photoelectric properties of the photodetectors are analyzed by the preparation of simple photodetectors. In this paper, the following main research achievements have been obtained: the hydrothermal method of preparing pyrite nanocrystalline has been studied. At the condition of S / FeN 3.75 / 1 ~ (-1) h ~ (-1) ~ (-1) h ~ (-1) pH ~ (12. 3) T ~ (-1) T ~ (2 +) ~ (200 鈩，

本文编号：1907100