In this work, we have designed and simulated a graphene field effect transistor (GFET) with the purpose of developing a sensitive biosensor for methanethiol, a biomarker for bacterial infections. The surface of a graphene layer is functionalized by manipulation of its surface structure and is used as the channel of the GFET. Two methods, doping the crystal structure of graphene and decorating the surface by transition metals (TMs), are utilized to change the electrical properties of the graphene layers to make them suitable as a channel of the GFET. The techniques also change the surface chemistry of the graphene, enhancing its adsorption characteristics and making binding between graphene and biomarker possible. All the physical parameters are calculated for various variants of graphene in the absence and presence of the biomarker using counterpoise energy-corrected density functional theory (DFT). The device was modelled using COMSOL Multiphysics. Our studies show that the sensitivity of the device is affected by structural parameters of the device, the electrical properties of the graphene, and with adsorption of the biomarker. It was found that the devices made of graphene layers decorated with TM show higher sensitivities toward detecting the biomarker compared with those made by doped graphene layers.

中文翻译：

---

带隙工程石墨烯FET的有限元建模及其在甲硫醇生物标志物传感中的应用

在这项工作中，我们设计并模拟了石墨烯场效应晶体管（GFET），其目的是开发一种灵敏的甲烷硫醇生物传感器，甲烷硫醇是细菌感染的生物标记。石墨烯层的表面通过操纵其表面结构而功能化，并用作GFET的沟道。掺杂石墨烯的晶体结构和通过过渡金属（TM）装饰表面的两种方法可用于改变石墨烯层的电性能，以使其适合用作GFET的沟道。该技术还改变了石墨烯的表面化学，增强了其吸附特性，并使石墨烯与生物标记物之间的结合成为可能。使用平衡性能量校正的密度泛函理论（DFT），在不存在和存在生物标记的情况下，针对石墨烯的各种变体计算了所有物理参数。该设备使用COMSOL Multiphysics建模。我们的研究表明，该设备的灵敏度受该设备的结构参数，石墨烯的电性能以及生物标记物吸附的影响。发现由用TM装饰的石墨烯层制成的装置与由掺杂的石墨烯层制成的装置相比，对检测生物标志物具有更高的灵敏度。并带有生物标志物的吸附。发现由用TM装饰的石墨烯层制成的装置与由掺杂的石墨烯层制成的装置相比，对检测生物标志物具有更高的灵敏度。并带有生物标志物的吸附。发现由用TM装饰的石墨烯层制成的装置与由掺杂的石墨烯层制成的装置相比，对检测生物标志物具有更高的灵敏度。