石墨烯/气凝胶结构硅异质结薄膜的镁热还原制备及其光电特性

项目名称： 石墨烯/气凝胶结构硅异质结薄膜的镁热还原制备及其光电特性

项目编号： No.51502077

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 陈珂

作者单位： 河南大学

项目金额： 20万元

中文摘要： 随着石墨烯的兴起，石墨烯/硅异质叠层结构的研究也迅速发展起来，成为新型肖特基光电器件领域的热点。然而，高灵敏度、高吸收率和宽光谱响应的硅基薄膜以及大面积、高质量和无转移石墨烯薄膜的可控制备与界面调控是高性能石墨烯/硅肖特基光电器件研究面临的挑战。本研究利用模板限制镁热共还原方法将氧化石墨烯/氧化硅气凝胶叠层薄膜一步转化为微结构及界面可控的石墨烯/纳米硅异质结薄膜。通过镁热还原反应实现氧化石墨烯还原程度和结晶度的提高以及能带的调控；以氧化硅代替危险的气态硅源合成纳米硅，并把气凝胶结构引入纳米硅薄膜以增强吸光效率和拓展光谱响应范围；原位生成石墨烯/硅异质界面以避免薄膜叠层转移过程。研究薄膜的光伏特性，分析薄膜光吸收、电压/电流、量子效率和开关比等特性的影响因素及变化规律，提出增强薄膜光电特性的方案，并探索其在肖特基光电探测器中的应用。

中文关键词： 石墨烯；气凝胶；纳米硅；镁热还原；光电

英文摘要： With the development of graphene, the research regarding graphene/silicon Schottky heterostructures has been rising rapidly in recent years. However, challenges still remain for high-performance silicon-based Schottky optoelectronic devices, which focuses on exploring large-area, high-quality and transfer-free graphene films as well as silicon thin films with high sensitivity, high absorption intensity, and wide spectral response. In this project, we demonstrate the controllable synthesis of graphene/nanocrystlline silicon aerogels (G/nc-SAG) thin-film heterostructures from the stacked graphene oxide/silica (G/SiO2) aerogels films by using a template-confined magnesiothermic co-reduction process. High crystallinity and modulating bandgap of graphene sheets can be achieved by magnesiothermic reduction of graphene oxide. The abundant silica resource for preparing nanocrystalline silicon films is utilized, instead of dangerous silane used in traditional methods, and the large surface area of aerogels endows the nanocrystalline silicon films with high efficiency of light absorption and wide spectral response. Besides, the in-situ growth of G/Si heterostructures without laminated transfer will be also achieved. The optical, optoelectronic properties of these G/nc-SAG heterostructured films will be probed. Moreover, the effects on optoelectronic properties (e. g. light absorption, I-V curves, quantum efficiency and on-off ratio) of these G/nc-SAG aerogel films will be investigated, and their applications in Schottky photodetectors will be also explored.

英文关键词： Graphene;Aerogels;Nanocrystalline silicon;Magnesiothermic reduction;Optoelectronics