Encapsulated graphene field-effect transistors for air stable operation

Abstract

In this work, we report the fabrication of encapsulated graphene field effects transistors (GFETs) with excellent air stability operation in ambient environment. Graphene's 2D nature makes its electronics properties very sensitive to the surrounding environment, and thus, non-encapsulated graphene devices show extensive vulnerability due to unintentional hole doping from the presence of water molecules and oxygen limiting their performance and use in real world applications. Encapsulating GFETs with a thin layer of parylene-C and aluminum deposited on top of the exposed graphene channel area resulted in devices with excellent electrical performance stability for an extended period of time. Moisture penetration is reduced significantly and carrier mobility degraded substantially less when compared to non-encapsulated control devices. Our CMOS compatible encapsulation method minimizes the problems of environmental doping and lifetime performance degradation, enabling the operation of air stable devices for next generation graphene-based electronics.

Effect of air on oxygen p‐doped graphene on SiO2

“…. Further experiments are necessary to fully clarify this dynamics and the interplay between specific molecules composing air atmosphere and oxygen molecules trapped on Gr or SiO 2 , it can be suggested that moisture could play a significant role in this context as it was found that water molecules could affect the doping .…”

Electrolyte-Gated Field Effect Transistors in Biological Sensing: A Survey of Electrolytes

“…Materials selection and transistor design are highly influential in determining the stability of an EGFET. Many approaches have been used for improving the stability of TFTs so far: the addition of additives [68], fine-tuning the composition of a component [113], encapsulation [114], barriers [51], or modification of the transistor geometry [115]. Further exploration is needed, especially to control the temperature, humidity, and electrochemical stability of EGFETs.…”

Nanostructured Graphene: An Active Component in Optoelectronic Devices

“…This effect is similar to oxygen doping of organic semiconductors [ 36 , 37 ], and this tendency explains the deviation of the minimum conductance point in many graphene FETs from zero V G . An effective encapsulation can minimize further air-induced doping and shift of transfer curves [ 38 ]. On the other hand, Giovannetti et al theoretically verified the charge-transfer doping of graphene by metal contacts, which can be regarded as another common source of unintentional doping in working devices [ 39 ].…”