Temperature-dependence of stress and elasticity in wet-transferred graphene membranes
Temperature-dependence of stress and elasticity in wet-transferred graphene membranes
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DOI：
10.1063/1.5006332
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发表时间：
2018-03-07
影响因子：
3.2
通讯作者：
Parpia, Jeevak M.
中科院分区：
文献类型：
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作者：
De Alba, Roberto;Abhilash, T. S.;Parpia, Jeevak M.
我们报告了在80 K至550 K的温度范围内测量两个悬浮石墨烯膜的机械性能。对于整个范围，在冷却和加热期间连续监测每个器械的谐振频率和品质因数。在300 K以下，我们还通过静电力测量了谐振频率的可调谐性，并对这些数据进行建模以确定石墨烯的张力和弹性模量;发现这两个参数在此范围内都强烈依赖于温度。在300 K以上，我们观察到共振频率（因此张力）在室温附近最小。这表明，热膨胀系数在低于约315 K的温度下为正，在更高的温度下为负。最后，当我们的石墨烯器件在300 K和550 K之间循环时，我们观察到谐振频率中的大的、可再现的滞后。回到300 K后，测得的频率随时间呈指数变化，时间常数近似为24 h。我们的结果与对原始石墨烯膜的预期相冲突，但与对由聚合物残留物薄层涂覆的石墨烯组成的复合膜的预期一致。出版社：AIP Publishing
We report measurements of the mechanical properties of two suspended graphene membranes in the temperature range of 80 K to 550 K. For this entire range, the resonant frequency and quality factor of each device were monitored continuously during cooling and heating. Below 300 K, we have additionally measured the resonant frequency's tunability via electrostatic force, and modeled this data to determine graphene's tension and elastic modulus; both of these parameters are found to be strongly temperature-dependent in this range. Above 300 K, we observe a resonant frequency (and therefore tension) minimum near room temperature. This suggests that the thermal expansion coefficient is positive for temperatures below roughly 315 K, and negative for higher temperatures. Lastly, we observe a large, reproducible hysteresis in the resonant frequency as our graphene devices are cycled between 300 K and 550 K. After returning to 300 K, the measured frequency evolves exponentially in time with a time constant of similar to 24 h. Our results clash with expectations for pristine graphene membranes, but are consistent with expectations for composite membranes composed of graphene coated by a thin layer of polymer residue. Published by AIP Publishing.