石墨烯的可控合成及其在纳米光电子器件中的应用研究

发布时间：2018-01-16 05:18

本文关键词：石墨烯的可控合成及其在纳米光电子器件中的应用研究　出处：《合肥工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：石墨烯(Graphene)是一种新型二维材料,原子级厚度、优异的性能和广泛的应用使得石墨烯被认为是未来纳米光电器件最有前途的候选材料。成功的合成与转移大面积石墨烯是实现石墨烯光电器件应用的基础。然而,石墨烯在实际应用过程中遇到了很多的技术难题,这不仅体现在大规模石墨烯的完整合成与完整转移上,还体现在提高基于石墨烯光电器件的性能上。基于这些技术难题,作者展开了对大面积石墨烯的合成与转移的探索和对基于石墨烯光电器件的研究。取得成果主要如下：1.系统地研究了大面积石墨烯的合成与转移,摸索出在铜基底合成石墨烯的合成条件,给出了石墨烯生长过程的示意曲线图,并对铜基底石墨烯的合成机理给出了阐述。同时也摸索了石墨烯的干法转移和湿法转移两种方法,对两种方法都进行了改善,达到了比较理想的要求,并对刻蚀液选择给出了具体的实验结论。2.利用CVD法生长的大面积石墨烯与传统半导体材料砷化镓相结合,并通过钝化工艺,制备出了自驱动高速近红外探测器。采用AlOx进行钝化制备BLG/AlOx/GaAs肖特基结,对BLG/AlOx/GaAs肖特基结进行了结构表征和光电性能表征；通过电学分析发现利用AlOx钝化的近红外光电探测器的在零偏压下对波长为850nm的近红外光的灵敏度比没有钝化的更高,钝化后的探测器的暗电流变小的同时,响应度也增加,同时也可以得到AlOx钝化后的近红外光电探测器的探测率(2.88×1011cmHz1/2W-1比未钝化的近红外探测器(7.3×109cmHz1/2W-1)要高出很多；更进一步对器件进行分析可以得到AlOx钝化的近红外光电探测器可以在超宽带的转换频率下工作,并且器件的响应速度也超快(Tr=320ns,τf=380ns)。3.利用CVD生长的大面积石墨烯与CdSe纳米带相结合,并通过表面等离子体共振增强效应,制备出了转化效率高的太阳能电池。采用双层石墨烯n型CdSe纳米带肖特基结制备太阳能电池,能量转化效率为0.4%,通过在CdSe纳米带上修饰金颗粒,大大提高了太阳能电池的光伏性能,能量转化效率提高到4.35%。通过吸收光谱得到修饰金颗粒后的CdSe纳米带对光的吸收变强促进转化效率的提高；通过对BLG/n-CdSe纳米带肖特基结的能带的分析,得出了该纳米太阳能电池的形成原理。
[Abstract]:Graphene (Graphene) is a new two-dimensional material with atomic thickness. Because of its excellent performance and wide application, graphene is considered to be the most promising candidate for nano-optoelectronic devices in the future. Successful synthesis and transfer of large areas of graphene are the basis for the application of graphene optoelectronic devices. . Graphene has encountered many technical problems in practical application, which is not only reflected in the complete synthesis and transfer of large-scale graphene. It is also reflected in improving the performance of graphene based optoelectronic devices. The author has explored the synthesis and transfer of large area graphene and studied the photovoltaic devices based on graphene. The main results are as follows: 1. The synthesis and transfer of large area graphene have been systematically studied. The conditions for the synthesis of graphene on copper substrate were found out, and the schematic curves of graphene growth process were given. The mechanism of the synthesis of graphene on copper substrate is also described. The dry and wet transfer methods of graphene are also explored. The two methods are improved and meet the ideal requirements. The specific experimental conclusion of etching solution selection is given. 2. The large area graphene grown by CVD method is combined with the traditional semiconductor material gallium arsenide, and the passivation process is adopted. The self-driving high speed near infrared detector was prepared and the BLG/AlOx/GaAs Schottky junction was prepared by AlOx passivation. The structure and photoelectric properties of BLG/AlOx/GaAs Schottky junction were characterized. Through electrical analysis, it is found that the near infrared photodetector passivated by AlOx has higher sensitivity to near-infrared light with wavelength of 850 nm at zero bias voltage than that without passivation. While the dark current of the passivated detector becomes smaller, the responsivity also increases. At the same time, the detectivity of the AlOx passivated near infrared photodetector is 2.88 脳 1011cmHz1 / 2W-1, which is higher than that of the unpassivated NIR photodetector (2 脳 1011cmHz1 / 2W-1). 7.3 脳 109 cm Hz1 / 2W-1) was much higher; Furthermore, the near infrared photodetector passivated by AlOx can work at UWB conversion frequency, and the response speed of the device is also very fast. Large area graphene grown by CVD was combined with CdSe nanobelts and enhanced by surface plasmon resonance (SPR). Solar cells with high conversion efficiency were prepared, and the energy conversion efficiency was 0.4% by using n-type CdSe nanospheres Schottky junction of double-layer graphene. The photovoltaic properties of the solar cells were greatly improved by modifying the gold particles on the CdSe nanoparticles. The energy conversion efficiency was increased to 4.35.The light absorption strength of the CdSe nanobelts modified by the modified gold nanoparticles promoted the conversion efficiency by absorption spectra. Based on the analysis of the band of Schottky junction of BLG/n-CdSe nanoband, the formation principle of the nano solar cell is obtained.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;TN29

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