Abstract
The solution-gate graphene field effect transistor
(Sg-GFET), as a popular sensing platform, its applications are still
hindered by the deficiency in all-solid-state, due to the dependence
on liquid-state gate-dielectric. Inspired by DNA hydrogel which can
provide microporous architecture to accommodate the fluidic analyte,
moreover, its combination with graphene is believed to foster
electron transport in the field of electrochemistry. We are
interested to take advantage of DNA hydrogel's solid-state and
capability for holding solution, and investigate whether it can
replace the traditional solution. So pure DNA hydrogel, their
complexes with GO (GO/DNA hydrogel) and RGO (RGO/DNA hydrogel) are
studied herein. Their micro-porous 3D morphologies are demonstrated,
their influences on the electrical characteristics of GFETs are
carefully examined and proved to be able to maintain the typical
bipolarity of Sg-GFET, firstly. Then, pure DNA hydrogel and GO/DNA
hydrogel are selected as the optimized gate-dielectrics, because of
their renewability after dehydration. Furthermore, by using
aptamer-based heavy metal ions (Pb2+ and Hg2+) detections
as proof-of-concept, the strategies for building the sensing
platform based on the optimized hydrogel dielectric-gated GFETs are
studied. It is found, for the purpose of substituting fluidic
dielectric in traditional Sg-GFET, the scheme of directly mounting
aptamer on graphene channel and coating pure DNA hydrogel on it is
demonstrated to be better than the strategies of using GO/DNA
hydrogel and hybriding aptamer probes in hydrogel scaffold. It is
explained according to surface charge sensing mechanism. At last,
the performances of the sensing platform based on the proposed DNA
hydrogel gated GFETs are testified by the detections and selectivity
examinations for Pb2+ and Hg2+. Conclusively, pure DNA
hydrogel is expected to be a promising candidate in the future
all-solid-state Sg-GFET.
Graphene field-effect transistor simulation with TCAD on top-gate dielectric influences
