锯齿形石墨烯纳米条带热电性质的研究

发布时间：2018-01-15 01:29

本文关键词：锯齿形石墨烯纳米条带热电性质的研究　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着新材料的研发和纳米技术的发展,器件尺寸的纳米化已成为了材料科学家的研究重点。由于介观体系中的尺寸和量子效应,纳米器件中的新材料展现出新颖的电学、热学和热电性质。这些奇异的性质吸引了越来越多实验和理论工作者的关注,使得相应的材料具有潜在的应用价值。本文运用Landauer—Buttiker输运理论与非平衡格林函数的方法,研究了石墨烯的热电性质,获得了一些有意义的结果。首先,我们运用格林函数方法,研究了锯齿形石墨纳米带中的声子热输运性质。计算结果表明,随着温度的升高,声子热导增大,最终趋于一个常数。改变锯齿形石墨烯纳米带宽度,热导也会增加。这个结果表明调制锯齿形石墨纳米带的带宽能用来调控热导。然后,根据Landauer—Buttiker公式,我们研究了石墨烯纳米带的电子输运性质。结果表明当锯齿形石墨烯纳米条带宽度增加时,电子电导和电子热导增加；当锯齿形石墨烯纳米带增长时,电子电导和电子热导不变；当温度升高时,电子电导不变,而电子热导增加。在上述工作的基础上,我们进一步研究了石墨烯纳米带的热电性质。结果表明增加锯齿形石墨烯纳米条带宽度,热电优值ZT均下降；升高温度时,热电优值ZT会相应地提高；增加锯齿形石墨烯纳米条带长度时,热电优值ZT不变。这些结果表明调制锯齿形石墨烯纳米条带的宽度和温度能有效地改善石墨纳米带的热电性能。
[Abstract]:With the development of new materials and nanotechnology, the nanocrystallization of device size has become the focus of material scientists, due to the size and quantum effects in mesoscopic systems. New materials in nanodevices exhibit novel electrical, thermal and thermoelectric properties, which have attracted more and more researchers' attention. In this paper, the thermoelectric properties of graphene are studied by using the Landauer-Buttiker transport theory and the method of non-equilibrium Green's function. Some significant results are obtained. Firstly, we use the Green's function method to study the phonon thermal transport properties in zigzag graphite nanoribbons. The calculated results show that the phonon thermal conductivity increases with the increase of temperature. Finally, it tends to a constant. Changing the width of zigzag graphene nanobelts, the thermal conductivity also increases. This result shows that the bandwidth of modulated zigzag graphene nanoribbons can be used to regulate thermal conductivity. According to the Landauer-Buttiker formula, we have studied the electron transport properties of graphene nanoribbons. The results show that when the width of zigzag graphene nanowires is increased, the electron transport properties of graphene nanoribbons are studied. Electronic conductivity and electronic thermal conductivity increased; When the zigzag graphene nanobelts grow, the electron conductance and the electron thermal conductivity will not change. When the temperature increases, the electron conductance remains the same and the electron thermal conductivity increases. On the basis of the above work. The thermoelectric properties of graphene nanoribbons are further studied. The results show that the increase of the width of zigzag graphene nanoribbons results in the decrease of the excellent thermoelectric values of ZT. When the temperature is raised, the excellent value of ZT will be increased accordingly. The results show that the width and temperature of zigzag graphene nanoribbons can effectively improve the thermoelectric properties of the zigzag graphene nanobelts by increasing the length of zigzag graphene nanoliths.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O613.71;TB383.1

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