论文标题
在大面积石墨烯场效应晶体管中，通过电阻噪声感知远程散装缺陷
Sensing Remote Bulk Defects Through Resistance Noise in a Large Area Graphene Field Effect Transistor
论文作者
论文摘要
底物在确定石墨烯场效应设备的运输和低频噪声行为方面起着至关重要的作用。通常，使用浓汤Si/Sio $ _2 $底物用于制造这些设备以进行有效的门控。捕获 - 隔开过程封闭于石墨烯/底物界面是石墨烯通道中电阻波动的主要来源，而由于大部分底物内部内部的任何远程电荷波动而引起的库仑波动会被浓度掺杂的底物有效地筛选。在这里，我们介绍了在轻度掺杂的Si/sio $ _2 $底物（N $ _a $ $ $ $ \ sim $ 10 $ 10 $^{15} $ cm $^{ - 3} $）上制备的大面积CVD石墨烯场效应晶体管（FET）的电子传输和低频噪声特性。通过对各种温度下的传输，噪声和电容的系统表征，我们揭示了远程SI/SIO $ _2 $接口可以严重影响石墨烯中的电荷传输，并且可以通过石墨烯通道来感知大部分硅基板内部的任何电荷波动。该设备的电阻（R）与后门电压（V $ _ {BG} $）的特性显示在SIO $ _2 $/SI接口形成的耗竭区域周围，电容（C） - 电压（V）测量。这些制造的设备上的低频噪声测量表明，接近耗尽区域的噪声幅度的峰值。这表明，由于缺乏Si/Sio $ _2 $接口处的任何电荷层，筛选能力降低，因此，可以通过移动性波动观察到硅基板内部深层库仑杂质的任何波动。离子液体门控石墨烯上同一基板上的噪声行为没有噪声上的峰值，可以通过界面捕获 - 脱落 - 脱落过程来解释。
Substrate plays a crucial role in determining transport and low frequency noise behavior of graphene field effect devices. Typically, heavily dope Si/SiO$_2$ substrate is used to fabricate these devices for efficient gating. Trapping-detrapping processes closed to the graphene/substrate interface are the dominant sources of resistance fluctuations in the graphene channel, while Coulomb fluctuations arising due to any remote charge fluctuations inside the bulk of the substrate are effectively screened by the heavily doped substrate. Here, we present electronic transport and low frequency noise characteristics of large area CVD graphene field effect transistor (FET) prepared on a lightly doped Si/SiO$_2$ substrate (N$_A$ $\sim$ 10$^{15}$cm$^{-3}$). Through a systematic characterization of transport, noise and capacitance at various temperature, we reveal that remote Si/SiO$_2$ interface can affect the charge transport in graphene severely and any charge fluctuations inside bulk of the silicon substrate can be sensed by the graphene channel. The resistance (R) vs. back gate voltage (V$_{bg}$) characteristics of the device shows a hump around the depletion region formed at the SiO$_2$/Si interface, confirmed by the capacitance (C) - Voltage (V) measurement. Low frequency noise measurement on these fabricated devices shows a peak in the noise amplitude close to the depletion region. This indicates that due to the absence of any charge layer at Si/SiO$_2$ interface, screening ability decreases and as a consequence, any fluctuations in the deep level coulomb impurities inside the silicon substrate can be observed as a noise in resistance in graphene channel via mobility fluctuations. Noise behavior on ionic liquid gated graphene on the same substrate exhibits no such peak in noise and can be explained by the interfacial trapping - detrapping processes closed to the graphene channel.
