Study Of Three-dimensional Wrinkled Graphene Field-effect Transistor Biosensor

Graphene field-effect transistor biosensors have been a hot research topic in the field of graphene sensors due to their technical features such as miniaturization,label-free,low cost,and fast response.Among them,ultra-sensitive detection in complex environments has been a hot issue of research.One of the reasons limiting its sensitivity is the effect of Debye shielding.In order to overcome the limitation of Debye shielding and improve the sensitivity of graphene field-effect transistor sensors,a three-dimensional wrinkled graphene preparation method is studied in this paper,and a three-dimensional wrinkled graphene field-effect transistor biosensor is constructed based on it to overcome the limitation of Debye shielding and improve the detection sensitivity by using its three-dimensional wrinkled morphology.In this paper,monolayer graphene was firstly prepared and transferred to polystyrene membrane using wet transfer method.Then the graphene and polystyrene membrane were heated,and the optimal heating temperature conditions,time conditions,etc.were experimentally explored to successfully prepare three-dimensional wrinkled graphene.The 3D wrinkled graphene was characterized by scanning electron microscopy,Raman spectroscopy and atomic force microscopy,and it was demonstrated that the 3D wrinkled graphene was successfully transferred to the polystyrene surface.Then,magnetron sputtering was used to prepare the source electrode and the drain electrode of the field-effect transistor on the polystyrene film,and the optimal sputtering power and time were determined.Finally,the surface functionalization modification of 3D wrinkled graphene,including PBASE and Aptamer modification,was performed,and the modification conditions were optimized to finally prepare 3D wrinkled graphene FET biosensors.In this paper,the experimental study was carried out with p H and ATP molecules as the detection objects.The results show that the detection sensitivity of ATP molecules reached 3.01 a M,showing ultra-sensitivity.Through the analysis,we suggest that the nanoscale wrinkles of graphene perturb the electrical double layer structure in the ionic solution and overcome the Debye shielding effect,thus leading to a higher detection sensitivity.The three-dimensional wrinkled graphene biosensor is not only simple to prepare and easy to fabricate,but also can improve the detection sensitivity by overcoming the limitation of Debye length,providing a new strategy for trace detection of bioactive molecules.